Include memo in the documented signature of copy.deepcopy()
* Include memo in the documented signature of copy.deepcopy()
The memo argument is mentioned lower on the doc page under writing a
`__deepcopy__` method, but is not included in the documented function signature.
This makes it easy to miss, and can lead to incorrect/buggy implementations of
`__deepcopy__` -- which is exatly what just happpend to me!
diff --git a/Doc/library/copy.rst b/Doc/library/copy.rst
index 2041d91..c7bd89f 100644
--- a/Doc/library/copy.rst
+++ b/Doc/library/copy.rst
@@ -22,7 +22,7 @@
Return a shallow copy of *x*.
-.. function:: deepcopy(x)
+.. function:: deepcopy(x[, memo])
Return a deep copy of *x*.
@@ -52,7 +52,7 @@
The :func:`deepcopy` function avoids these problems by:
-* keeping a "memo" dictionary of objects already copied during the current
+* keeping a ``memo`` dictionary of objects already copied during the current
copying pass; and
* letting user-defined classes override the copying operation or the set of
@@ -82,7 +82,7 @@
special methods :meth:`__copy__` and :meth:`__deepcopy__`. The former is called
to implement the shallow copy operation; no additional arguments are passed.
The latter is called to implement the deep copy operation; it is passed one
-argument, the memo dictionary. If the :meth:`__deepcopy__` implementation needs
+argument, the ``memo`` dictionary. If the :meth:`__deepcopy__` implementation needs
to make a deep copy of a component, it should call the :func:`deepcopy` function
with the component as first argument and the memo dictionary as second argument.