typo fix
diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index 42dba72..f8341d1 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -588,7 +588,7 @@
:param bytes data: PEM data to load.
:param bytes password: The password to use if the data is encrypted.
- Should be ``None`` is the data is not encrypted.
+ Should be ``None`` if the data is not encrypted.
:return: A new instance of the appropriate type of private key that the
serialized data contains.
:raises ValueError: If the data could not be deserialized.