Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/networkx/utils/contextmanagers.py

@@ -0,0 +1,42 @@
+from contextlib import contextmanager
+import warnings
+
+__all__ = ["reversed"]
+
+
+@contextmanager
+def reversed(G):
+    """A context manager for temporarily reversing a directed graph in place.
+
+    This is a no-op for undirected graphs.
+
+    Parameters
+    ----------
+    G : graph
+        A NetworkX graph.
+
+    Warning
+    -------
+    The reversed context manager is deprecated in favor
+    of G.reverse(copy=False). The view allows multiple threads to use the
+    same graph without confusion while the context manager does not.
+    This context manager is scheduled to be removed in version 3.0.
+    """
+    msg = (
+        "context manager reversed is deprecated and to be removed in 3.0."
+        "Use G.reverse(copy=False) if G.is_directed() else G instead."
+    )
+    warnings.warn(msg, DeprecationWarning)
+
+    directed = G.is_directed()
+    if directed:
+        G._pred, G._succ = G._succ, G._pred
+        G._adj = G._succ
+
+    try:
+        yield
+    finally:
+        if directed:
+            # Reverse the reverse.
+            G._pred, G._succ = G._succ, G._pred
+            G._adj = G._succ