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diff --git a/python/gevent/exceptions.py b/python/gevent/exceptions.py
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+++ b/python/gevent/exceptions.py
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+# -*- coding: utf-8 -*-
+# copyright 2018 gevent
+"""
+Exceptions.
+
+.. versionadded:: 1.3b1
+
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+
+__all__ = [
+    'LoopExit',
+]
+
+
+class LoopExit(Exception):
+    """
+    Exception thrown when the hub finishes running (`gevent.hub.Hub.run`
+    would return).
+
+    In a normal application, this is never thrown or caught
+    explicitly. The internal implementation of functions like
+    :meth:`gevent.hub.Hub.join` and :func:`gevent.joinall` may catch it, but user code
+    generally should not.
+
+    .. caution::
+       Errors in application programming can also lead to this exception being
+       raised. Some examples include (but are not limited too):
+
+       - greenlets deadlocking on a lock;
+       - using a socket or other gevent object with native thread
+         affinity from a different thread
+
+    """
+
+    def __repr__(self):
+        # pylint:disable=unsubscriptable-object
+        if len(self.args) == 3: # From the hub
+            import pprint
+            return "%s\n\tHub: %s\n\tHandles:\n%s" % (
+                self.args[0], self.args[1],
+                pprint.pformat(self.args[2])
+            )
+        return Exception.__repr__(self)
+
+    def __str__(self):
+        return repr(self)
+
+class BlockingSwitchOutError(AssertionError):
+    """
+    Raised when a gevent synchronous function is called from a
+    low-level event loop callback.
+
+    This is usually a programming error.
+    """
+
+
+class InvalidSwitchError(AssertionError):
+    """
+    Raised when the event loop returns control to a greenlet in an
+    unexpected way.
+
+    This is usually a bug in gevent, greenlet, or the event loop.
+    """
+
+class ConcurrentObjectUseError(AssertionError):
+    """
+    Raised when an object is used (waited on) by two greenlets
+    independently, meaning the object was entered into a blocking
+    state by one greenlet and then another while still blocking in the
+    first one.
+
+    This is usually a programming error.
+
+    .. seealso:: `gevent.socket.wait`
+    """