Fix some issues with copy_docstrings
diff --git a/google/auth/_helpers.py b/google/auth/_helpers.py
index 9fe2caa..92c6c83 100644
--- a/google/auth/_helpers.py
+++ b/google/auth/_helpers.py
@@ -22,9 +22,27 @@
def copy_docstring(source_class):
- """Decorator that copies a method's docstring from another class."""
+ """Decorator that copies a method's docstring from another class.
+
+ Args:
+ source_class (type): The class that has the documented method.
+
+ Returns:
+ Callable: A decorator that will copy the docstring of the same
+ named method in the source class to the decorated method.
+ """
def decorator(method):
- """Decorator implementation."""
+ """Decorator implementation.
+
+ Args:
+ method: The method to copy the docstring to.
+
+ Returns:
+ Callable: the same method passed in with an updated docstring.
+
+ Raises:
+ ValueError: if the method already has a docstring.
+ """
if method.__doc__:
raise ValueError('Method already has a docstring.')