Ensure `function` is actually a function.

Plus minor cleanup

IPython/core/events.py

@@ -14,6 +14,7 b' events and the arguments which will be passed to them.'
 """
 
 from functools import wraps
+from inspect import isfunction
 try:
     from inspect import getfullargspec
 except:
@@ -79,10 +80,10 b' class EventManager(object):'
             raise TypeError('Need a callable, got %r' % function)
 
         callback_proto = available_events.get(event)
-        if (callable(callback_proto) and
+        if (isfunction(callback_proto) and isfunction(function) and
             len(getfullargspec(callback_proto).args) > 0 and
             len(getfullargspec(function).args) == 0):
-            # `callback_proto` requires args but `function` does not, so a
+            # `callback_proto` has args but `function` does not, so a
             # compatibility wrapper is needed.
             self.callbacks[event].append(_compatibility_wrapper_for(function))
         else:

docs/source/config/callbacks.rst

@@ -70,11 +70,9 b' argument, even though the actual result is not yet available.'
 post_run_cell
 -------------
 
-``post_run_cell`` runs after interactive execution.
-It can be used to cleanup or notify or perform operations on any side effects
-produced during execution.
-For instance, the inline matplotlib backend uses this event to display any
-figures created but not explicitly displayed during the course of the cell.
+``post_run_cell`` runs after interactive execution (e.g. a cell in a notebook).
+It can be used to cleanup or notify or perform operations on any side effects produced during execution.
+For instance, the inline matplotlib backend uses this event to display any figures created but not explicitly displayed during the course of the cell.
 The object which will be returned as the execution result is provided as an
 argument.
 
@@ -84,20 +82,6 b' post_execute'
 The same as ``pre_execute``, ``post_execute`` is like ``post_run_cell``,
 but fires for *all* executions, not just interactive ones.
 
-finally_run_cell
--------------
-
-``finally_run_cell`` is like ``post_run_cell``, but fires after *all* executions
-(even when, for example, a ``SyntaxError`` was raised).
-Additionally, the execution result is provided as an argument.
-
-finally_execute
-------------
-
-``finally_execute`` is like ``post_execute``, but fires after *all* executions
-(even when, for example, a ``SyntaxError`` was raised).
-Additionally, the execution result is provided as an argument.
-
 
 .. seealso::