Release v1.6.0 (#324)

* Update version and changelog for v1.6.0
* Update docs
diff --git a/docs/dyn/pubsub_v1.projects.snapshots.html b/docs/dyn/pubsub_v1.projects.snapshots.html
index 32dbf2c..b872beb 100644
--- a/docs/dyn/pubsub_v1.projects.snapshots.html
+++ b/docs/dyn/pubsub_v1.projects.snapshots.html
@@ -75,105 +75,324 @@
 <h1><a href="pubsub_v1.html">Google Cloud Pub/Sub API</a> . <a href="pubsub_v1.projects.html">projects</a> . <a href="pubsub_v1.projects.snapshots.html">snapshots</a></h1>
 <h2>Instance Methods</h2>
 <p class="toc_element">
-  <code><a href="#getIamPolicy">getIamPolicy(resource, x__xgafv=None)</a></code></p>
-<p class="firstline">Gets the access control policy for a resource. Returns an empty policy if the resource exists and does not have a policy set.</p>
+  <code><a href="#getIamPolicy">getIamPolicy(resource=None, x__xgafv=None)</a></code></p>
+<p class="firstline">Gets the access control policy for a resource.</p>
 <p class="toc_element">
-  <code><a href="#setIamPolicy">setIamPolicy(resource, body, x__xgafv=None)</a></code></p>
-<p class="firstline">Sets the access control policy on the specified resource. Replaces any existing policy.</p>
+  <code><a href="#setIamPolicy">setIamPolicy(resource=None, body, x__xgafv=None)</a></code></p>
+<p class="firstline">Sets the access control policy on the specified resource. Replaces any</p>
 <p class="toc_element">
-  <code><a href="#testIamPermissions">testIamPermissions(resource, body, x__xgafv=None)</a></code></p>
+  <code><a href="#testIamPermissions">testIamPermissions(resource=None, body, x__xgafv=None)</a></code></p>
 <p class="firstline">Returns permissions that a caller has on the specified resource.</p>
 <h3>Method Details</h3>
 <div class="method">
-    <code class="details" id="getIamPolicy">getIamPolicy(resource, x__xgafv=None)</code>
-  <pre>Gets the access control policy for a resource. Returns an empty policy if the resource exists and does not have a policy set.
+    <code class="details" id="getIamPolicy">getIamPolicy(resource=None, x__xgafv=None)</code>
+  <pre>Gets the access control policy for a resource.
+Returns an empty policy if the resource exists and does not have a policy
+set.
 
 Args:
-  resource: string, REQUIRED: The resource for which the policy is being requested. `resource` is usually specified as a path. For example, a Project resource is specified as `projects/{project}`. (required)
+  resource: string, REQUIRED: The resource for which the policy is being requested.
+`resource` is usually specified as a path. For example, a Project
+resource is specified as `projects/{project}`. (required)
   x__xgafv: string, V1 error format.
+    Allowed values
+      1 - v1 error format
+      2 - v2 error format
 
 Returns:
   An object of the form:
 
-    { # Defines an Identity and Access Management (IAM) policy. It is used to specify access control policies for Cloud Platform resources. A `Policy` consists of a list of `bindings`. A `Binding` binds a list of `members` to a `role`, where the members can be user accounts, Google groups, Google domains, and service accounts. A `role` is a named list of permissions defined by IAM. **Example** { "bindings": [ { "role": "roles/owner", "members": [ "user:mike@example.com", "group:admins@example.com", "domain:google.com", "serviceAccount:my-other-app@appspot.gserviceaccount.com", ] }, { "role": "roles/viewer", "members": ["user:sean@example.com"] } ] } For a description of IAM and its features, see the [IAM developer's guide](https://cloud.google.com/iam).
-    "bindings": [ # Associates a list of `members` to a `role`. Multiple `bindings` must not be specified for the same `role`. `bindings` with no members will result in an error.
+    { # Defines an Identity and Access Management (IAM) policy. It is used to
+      # specify access control policies for Cloud Platform resources.
+      #
+      #
+      # A `Policy` consists of a list of `bindings`. A `Binding` binds a list of
+      # `members` to a `role`, where the members can be user accounts, Google groups,
+      # Google domains, and service accounts. A `role` is a named list of permissions
+      # defined by IAM.
+      #
+      # **Example**
+      #
+      #     {
+      #       "bindings": [
+      #         {
+      #           "role": "roles/owner",
+      #           "members": [
+      #             "user:mike@example.com",
+      #             "group:admins@example.com",
+      #             "domain:google.com",
+      #             "serviceAccount:my-other-app@appspot.gserviceaccount.com",
+      #           ]
+      #         },
+      #         {
+      #           "role": "roles/viewer",
+      #           "members": ["user:sean@example.com"]
+      #         }
+      #       ]
+      #     }
+      #
+      # For a description of IAM and its features, see the
+      # [IAM developer's guide](https://cloud.google.com/iam).
+    "bindings": [ # Associates a list of `members` to a `role`.
+        # Multiple `bindings` must not be specified for the same `role`.
+        # `bindings` with no members will result in an error.
       { # Associates `members` with a `role`.
-        "role": "A String", # Role that is assigned to `members`. For example, `roles/viewer`, `roles/editor`, or `roles/owner`. Required
-        "members": [ # Specifies the identities requesting access for a Cloud Platform resource. `members` can have the following values: * `allUsers`: A special identifier that represents anyone who is on the internet; with or without a Google account. * `allAuthenticatedUsers`: A special identifier that represents anyone who is authenticated with a Google account or a service account. * `user:{emailid}`: An email address that represents a specific Google account. For example, `alice@gmail.com` or `joe@example.com`. * `serviceAccount:{emailid}`: An email address that represents a service account. For example, `my-other-app@appspot.gserviceaccount.com`. * `group:{emailid}`: An email address that represents a Google group. For example, `admins@example.com`. * `domain:{domain}`: A Google Apps domain name that represents all the users of that domain. For example, `google.com` or `example.com`.
+        "role": "A String", # Role that is assigned to `members`.
+            # For example, `roles/viewer`, `roles/editor`, or `roles/owner`.
+            # Required
+        "members": [ # Specifies the identities requesting access for a Cloud Platform resource.
+            # `members` can have the following values:
+            #
+            # * `allUsers`: A special identifier that represents anyone who is
+            #    on the internet; with or without a Google account.
+            #
+            # * `allAuthenticatedUsers`: A special identifier that represents anyone
+            #    who is authenticated with a Google account or a service account.
+            #
+            # * `user:{emailid}`: An email address that represents a specific Google
+            #    account. For example, `alice@gmail.com` or `joe@example.com`.
+            #
+            #
+            # * `serviceAccount:{emailid}`: An email address that represents a service
+            #    account. For example, `my-other-app@appspot.gserviceaccount.com`.
+            #
+            # * `group:{emailid}`: An email address that represents a Google group.
+            #    For example, `admins@example.com`.
+            #
+            # * `domain:{domain}`: A Google Apps domain name that represents all the
+            #    users of that domain. For example, `google.com` or `example.com`.
+            #
           "A String",
         ],
       },
     ],
+    "etag": "A String", # `etag` is used for optimistic concurrency control as a way to help
+        # prevent simultaneous updates of a policy from overwriting each other.
+        # It is strongly suggested that systems make use of the `etag` in the
+        # read-modify-write cycle to perform policy updates in order to avoid race
+        # conditions: An `etag` is returned in the response to `getIamPolicy`, and
+        # systems are expected to put that etag in the request to `setIamPolicy` to
+        # ensure that their change will be applied to the same version of the policy.
+        #
+        # If no `etag` is provided in the call to `setIamPolicy`, then the existing
+        # policy is overwritten blindly.
     "version": 42, # Version of the `Policy`. The default version is 0.
-    "etag": "A String", # `etag` is used for optimistic concurrency control as a way to help prevent simultaneous updates of a policy from overwriting each other. It is strongly suggested that systems make use of the `etag` in the read-modify-write cycle to perform policy updates in order to avoid race conditions: An `etag` is returned in the response to `getIamPolicy`, and systems are expected to put that etag in the request to `setIamPolicy` to ensure that their change will be applied to the same version of the policy. If no `etag` is provided in the call to `setIamPolicy`, then the existing policy is overwritten blindly.
   }</pre>
 </div>
 
 <div class="method">
-    <code class="details" id="setIamPolicy">setIamPolicy(resource, body, x__xgafv=None)</code>
-  <pre>Sets the access control policy on the specified resource. Replaces any existing policy.
+    <code class="details" id="setIamPolicy">setIamPolicy(resource=None, body, x__xgafv=None)</code>
+  <pre>Sets the access control policy on the specified resource. Replaces any
+existing policy.
 
 Args:
-  resource: string, REQUIRED: The resource for which the policy is being specified. `resource` is usually specified as a path. For example, a Project resource is specified as `projects/{project}`. (required)
+  resource: string, REQUIRED: The resource for which the policy is being specified.
+`resource` is usually specified as a path. For example, a Project
+resource is specified as `projects/{project}`. (required)
   body: object, The request body. (required)
     The object takes the form of:
 
 { # Request message for `SetIamPolicy` method.
-    "policy": { # Defines an Identity and Access Management (IAM) policy. It is used to specify access control policies for Cloud Platform resources. A `Policy` consists of a list of `bindings`. A `Binding` binds a list of `members` to a `role`, where the members can be user accounts, Google groups, Google domains, and service accounts. A `role` is a named list of permissions defined by IAM. **Example** { "bindings": [ { "role": "roles/owner", "members": [ "user:mike@example.com", "group:admins@example.com", "domain:google.com", "serviceAccount:my-other-app@appspot.gserviceaccount.com", ] }, { "role": "roles/viewer", "members": ["user:sean@example.com"] } ] } For a description of IAM and its features, see the [IAM developer's guide](https://cloud.google.com/iam). # REQUIRED: The complete policy to be applied to the `resource`. The size of the policy is limited to a few 10s of KB. An empty policy is a valid policy but certain Cloud Platform services (such as Projects) might reject them.
-      "bindings": [ # Associates a list of `members` to a `role`. Multiple `bindings` must not be specified for the same `role`. `bindings` with no members will result in an error.
+    "policy": { # Defines an Identity and Access Management (IAM) policy. It is used to # REQUIRED: The complete policy to be applied to the `resource`. The size of
+        # the policy is limited to a few 10s of KB. An empty policy is a
+        # valid policy but certain Cloud Platform services (such as Projects)
+        # might reject them.
+        # specify access control policies for Cloud Platform resources.
+        #
+        #
+        # A `Policy` consists of a list of `bindings`. A `Binding` binds a list of
+        # `members` to a `role`, where the members can be user accounts, Google groups,
+        # Google domains, and service accounts. A `role` is a named list of permissions
+        # defined by IAM.
+        #
+        # **Example**
+        #
+        #     {
+        #       "bindings": [
+        #         {
+        #           "role": "roles/owner",
+        #           "members": [
+        #             "user:mike@example.com",
+        #             "group:admins@example.com",
+        #             "domain:google.com",
+        #             "serviceAccount:my-other-app@appspot.gserviceaccount.com",
+        #           ]
+        #         },
+        #         {
+        #           "role": "roles/viewer",
+        #           "members": ["user:sean@example.com"]
+        #         }
+        #       ]
+        #     }
+        #
+        # For a description of IAM and its features, see the
+        # [IAM developer's guide](https://cloud.google.com/iam).
+      "bindings": [ # Associates a list of `members` to a `role`.
+          # Multiple `bindings` must not be specified for the same `role`.
+          # `bindings` with no members will result in an error.
         { # Associates `members` with a `role`.
-          "role": "A String", # Role that is assigned to `members`. For example, `roles/viewer`, `roles/editor`, or `roles/owner`. Required
-          "members": [ # Specifies the identities requesting access for a Cloud Platform resource. `members` can have the following values: * `allUsers`: A special identifier that represents anyone who is on the internet; with or without a Google account. * `allAuthenticatedUsers`: A special identifier that represents anyone who is authenticated with a Google account or a service account. * `user:{emailid}`: An email address that represents a specific Google account. For example, `alice@gmail.com` or `joe@example.com`. * `serviceAccount:{emailid}`: An email address that represents a service account. For example, `my-other-app@appspot.gserviceaccount.com`. * `group:{emailid}`: An email address that represents a Google group. For example, `admins@example.com`. * `domain:{domain}`: A Google Apps domain name that represents all the users of that domain. For example, `google.com` or `example.com`.
+          "role": "A String", # Role that is assigned to `members`.
+              # For example, `roles/viewer`, `roles/editor`, or `roles/owner`.
+              # Required
+          "members": [ # Specifies the identities requesting access for a Cloud Platform resource.
+              # `members` can have the following values:
+              #
+              # * `allUsers`: A special identifier that represents anyone who is
+              #    on the internet; with or without a Google account.
+              #
+              # * `allAuthenticatedUsers`: A special identifier that represents anyone
+              #    who is authenticated with a Google account or a service account.
+              #
+              # * `user:{emailid}`: An email address that represents a specific Google
+              #    account. For example, `alice@gmail.com` or `joe@example.com`.
+              #
+              #
+              # * `serviceAccount:{emailid}`: An email address that represents a service
+              #    account. For example, `my-other-app@appspot.gserviceaccount.com`.
+              #
+              # * `group:{emailid}`: An email address that represents a Google group.
+              #    For example, `admins@example.com`.
+              #
+              # * `domain:{domain}`: A Google Apps domain name that represents all the
+              #    users of that domain. For example, `google.com` or `example.com`.
+              #
             "A String",
           ],
         },
       ],
+      "etag": "A String", # `etag` is used for optimistic concurrency control as a way to help
+          # prevent simultaneous updates of a policy from overwriting each other.
+          # It is strongly suggested that systems make use of the `etag` in the
+          # read-modify-write cycle to perform policy updates in order to avoid race
+          # conditions: An `etag` is returned in the response to `getIamPolicy`, and
+          # systems are expected to put that etag in the request to `setIamPolicy` to
+          # ensure that their change will be applied to the same version of the policy.
+          #
+          # If no `etag` is provided in the call to `setIamPolicy`, then the existing
+          # policy is overwritten blindly.
       "version": 42, # Version of the `Policy`. The default version is 0.
-      "etag": "A String", # `etag` is used for optimistic concurrency control as a way to help prevent simultaneous updates of a policy from overwriting each other. It is strongly suggested that systems make use of the `etag` in the read-modify-write cycle to perform policy updates in order to avoid race conditions: An `etag` is returned in the response to `getIamPolicy`, and systems are expected to put that etag in the request to `setIamPolicy` to ensure that their change will be applied to the same version of the policy. If no `etag` is provided in the call to `setIamPolicy`, then the existing policy is overwritten blindly.
     },
   }
 
   x__xgafv: string, V1 error format.
+    Allowed values
+      1 - v1 error format
+      2 - v2 error format
 
 Returns:
   An object of the form:
 
-    { # Defines an Identity and Access Management (IAM) policy. It is used to specify access control policies for Cloud Platform resources. A `Policy` consists of a list of `bindings`. A `Binding` binds a list of `members` to a `role`, where the members can be user accounts, Google groups, Google domains, and service accounts. A `role` is a named list of permissions defined by IAM. **Example** { "bindings": [ { "role": "roles/owner", "members": [ "user:mike@example.com", "group:admins@example.com", "domain:google.com", "serviceAccount:my-other-app@appspot.gserviceaccount.com", ] }, { "role": "roles/viewer", "members": ["user:sean@example.com"] } ] } For a description of IAM and its features, see the [IAM developer's guide](https://cloud.google.com/iam).
-    "bindings": [ # Associates a list of `members` to a `role`. Multiple `bindings` must not be specified for the same `role`. `bindings` with no members will result in an error.
+    { # Defines an Identity and Access Management (IAM) policy. It is used to
+      # specify access control policies for Cloud Platform resources.
+      #
+      #
+      # A `Policy` consists of a list of `bindings`. A `Binding` binds a list of
+      # `members` to a `role`, where the members can be user accounts, Google groups,
+      # Google domains, and service accounts. A `role` is a named list of permissions
+      # defined by IAM.
+      #
+      # **Example**
+      #
+      #     {
+      #       "bindings": [
+      #         {
+      #           "role": "roles/owner",
+      #           "members": [
+      #             "user:mike@example.com",
+      #             "group:admins@example.com",
+      #             "domain:google.com",
+      #             "serviceAccount:my-other-app@appspot.gserviceaccount.com",
+      #           ]
+      #         },
+      #         {
+      #           "role": "roles/viewer",
+      #           "members": ["user:sean@example.com"]
+      #         }
+      #       ]
+      #     }
+      #
+      # For a description of IAM and its features, see the
+      # [IAM developer's guide](https://cloud.google.com/iam).
+    "bindings": [ # Associates a list of `members` to a `role`.
+        # Multiple `bindings` must not be specified for the same `role`.
+        # `bindings` with no members will result in an error.
       { # Associates `members` with a `role`.
-        "role": "A String", # Role that is assigned to `members`. For example, `roles/viewer`, `roles/editor`, or `roles/owner`. Required
-        "members": [ # Specifies the identities requesting access for a Cloud Platform resource. `members` can have the following values: * `allUsers`: A special identifier that represents anyone who is on the internet; with or without a Google account. * `allAuthenticatedUsers`: A special identifier that represents anyone who is authenticated with a Google account or a service account. * `user:{emailid}`: An email address that represents a specific Google account. For example, `alice@gmail.com` or `joe@example.com`. * `serviceAccount:{emailid}`: An email address that represents a service account. For example, `my-other-app@appspot.gserviceaccount.com`. * `group:{emailid}`: An email address that represents a Google group. For example, `admins@example.com`. * `domain:{domain}`: A Google Apps domain name that represents all the users of that domain. For example, `google.com` or `example.com`.
+        "role": "A String", # Role that is assigned to `members`.
+            # For example, `roles/viewer`, `roles/editor`, or `roles/owner`.
+            # Required
+        "members": [ # Specifies the identities requesting access for a Cloud Platform resource.
+            # `members` can have the following values:
+            #
+            # * `allUsers`: A special identifier that represents anyone who is
+            #    on the internet; with or without a Google account.
+            #
+            # * `allAuthenticatedUsers`: A special identifier that represents anyone
+            #    who is authenticated with a Google account or a service account.
+            #
+            # * `user:{emailid}`: An email address that represents a specific Google
+            #    account. For example, `alice@gmail.com` or `joe@example.com`.
+            #
+            #
+            # * `serviceAccount:{emailid}`: An email address that represents a service
+            #    account. For example, `my-other-app@appspot.gserviceaccount.com`.
+            #
+            # * `group:{emailid}`: An email address that represents a Google group.
+            #    For example, `admins@example.com`.
+            #
+            # * `domain:{domain}`: A Google Apps domain name that represents all the
+            #    users of that domain. For example, `google.com` or `example.com`.
+            #
           "A String",
         ],
       },
     ],
+    "etag": "A String", # `etag` is used for optimistic concurrency control as a way to help
+        # prevent simultaneous updates of a policy from overwriting each other.
+        # It is strongly suggested that systems make use of the `etag` in the
+        # read-modify-write cycle to perform policy updates in order to avoid race
+        # conditions: An `etag` is returned in the response to `getIamPolicy`, and
+        # systems are expected to put that etag in the request to `setIamPolicy` to
+        # ensure that their change will be applied to the same version of the policy.
+        #
+        # If no `etag` is provided in the call to `setIamPolicy`, then the existing
+        # policy is overwritten blindly.
     "version": 42, # Version of the `Policy`. The default version is 0.
-    "etag": "A String", # `etag` is used for optimistic concurrency control as a way to help prevent simultaneous updates of a policy from overwriting each other. It is strongly suggested that systems make use of the `etag` in the read-modify-write cycle to perform policy updates in order to avoid race conditions: An `etag` is returned in the response to `getIamPolicy`, and systems are expected to put that etag in the request to `setIamPolicy` to ensure that their change will be applied to the same version of the policy. If no `etag` is provided in the call to `setIamPolicy`, then the existing policy is overwritten blindly.
   }</pre>
 </div>
 
 <div class="method">
-    <code class="details" id="testIamPermissions">testIamPermissions(resource, body, x__xgafv=None)</code>
+    <code class="details" id="testIamPermissions">testIamPermissions(resource=None, body, x__xgafv=None)</code>
   <pre>Returns permissions that a caller has on the specified resource.
+If the resource does not exist, this will return an empty set of
+permissions, not a NOT_FOUND error.
 
 Args:
-  resource: string, REQUIRED: The resource for which the policy detail is being requested. `resource` is usually specified as a path. For example, a Project resource is specified as `projects/{project}`. (required)
+  resource: string, REQUIRED: The resource for which the policy detail is being requested.
+`resource` is usually specified as a path. For example, a Project
+resource is specified as `projects/{project}`. (required)
   body: object, The request body. (required)
     The object takes the form of:
 
 { # Request message for `TestIamPermissions` method.
-    "permissions": [ # The set of permissions to check for the `resource`. Permissions with wildcards (such as '*' or 'storage.*') are not allowed. For more information see [IAM Overview](https://cloud.google.com/iam/docs/overview#permissions).
+    "permissions": [ # The set of permissions to check for the `resource`. Permissions with
+        # wildcards (such as '*' or 'storage.*') are not allowed. For more
+        # information see
+        # [IAM Overview](https://cloud.google.com/iam/docs/overview#permissions).
       "A String",
     ],
   }
 
   x__xgafv: string, V1 error format.
+    Allowed values
+      1 - v1 error format
+      2 - v2 error format
 
 Returns:
   An object of the form:
 
     { # Response message for `TestIamPermissions` method.
-    "permissions": [ # A subset of `TestPermissionsRequest.permissions` that the caller is allowed.
+    "permissions": [ # A subset of `TestPermissionsRequest.permissions` that the caller is
+        # allowed.
       "A String",
     ],
   }</pre>