#1090076: explain the behavior of *vars* in get() better.
diff --git a/Doc/library/configparser.rst b/Doc/library/configparser.rst
index f77a5b8..25e3cbe 100644
--- a/Doc/library/configparser.rst
+++ b/Doc/library/configparser.rst
@@ -44,7 +44,7 @@
On top of the core functionality, :class:`SafeConfigParser` supports
interpolation. This means values can contain format strings which refer to
other values in the same section, or values in a special ``DEFAULT`` section.
-Additional defaults can be provided on initialization and retrieval.
+Additional defaults can be provided on initialization.
For example::
@@ -92,8 +92,7 @@
manner by both parsers.
Default values can be specified by passing them as a dictionary when
-constructing the :class:`SafeConfigParser`. Additional defaults may be passed
-to the :meth:`get` method which will override all others.
+constructing the :class:`SafeConfigParser`.
Sections are normally stored in an :class:`collections.OrderedDict` which
maintains the order of all keys. An alternative dictionary type can be passed
@@ -418,10 +417,13 @@
.. method:: ConfigParser.get(section, option, raw=False, vars=None)
- Get an *option* value for the named *section*. All the ``'%'``
- interpolations are expanded in the return values, based on the defaults
- passed into the :meth:`__init__` method, as well as the options *vars*
- provided, unless the *raw* argument is true.
+ Get an *option* value for the named *section*. If *vars* is provided, it
+ must be a dictionary. The *option* is looked up in *vars* (if provided),
+ *section*, and in *defaults* in that order.
+
+ All the ``'%'`` interpolations are expanded in the return values, unless the
+ *raw* argument is true. Values for interpolation keys are looked up in the
+ same manner as the option.
.. method:: ConfigParser.items(section, raw=False, vars=None)
diff --git a/Lib/configparser.py b/Lib/configparser.py
index 7ad24d8..6e38f26 100644
--- a/Lib/configparser.py
+++ b/Lib/configparser.py
@@ -661,11 +661,12 @@
def get(self, section, option, raw=False, vars=None):
"""Get an option value for a given section.
- All % interpolations are expanded in the return values, based on the
- defaults passed into the constructor, unless the optional argument
- `raw' is true. Additional substitutions may be provided using the
- `vars' argument, which must be a dictionary whose contents overrides
- any pre-existing defaults.
+ If `vars' is provided, it must be a dictionary. The option is looked up
+ in `vars' (if provided), `section', and in `defaults' in that order.
+
+ All % interpolations are expanded in the return values, unless the
+ optional argument `raw' is true. Values for interpolation keys are
+ looked up in the same manner as the option.
The section DEFAULT is special.
"""