docs: def get_or_create_exh_obj(full_cname=False, exclude=None, callables_fname=None):
      r"""
      Return global exception handler if set, otherwise create a new one and return it.
  
      :param full_cname: Flag that indicates whether fully qualified
                         function/method/class property names are obtained for
                         functions/methods/class properties that use the
                         exception manager (True) or not (False).
  
                         There is a performance penalty if the flag is True as
                         the call stack needs to be traced. This argument is
                         only relevant if the global exception handler is not
                         set and a new one is created
      :type  full_cname: boolean
  
      :param exclude: Module exclusion list. A particular callable in an
                      otherwise fully qualified name is omitted if it belongs
                      to a module in this list. If None all callables are
                      included
      :type  exclude: list of strings or None
  
      :param callables_fname: File name that contains traced modules information.
                              File can be produced by either the
                              :py:meth:`pexdoc.pinspect.Callables.save` or
                              :py:meth:`pexdoc.ExHandle.save_callables`
                              methods
      :type  callables_fname: :ref:`FileNameExists` or None
  
      :rtype: :py:class:`pexdoc.ExHandle`
  
      :raises:
       * OSError (File *[callables_fname]* could not be found
  
       * RuntimeError (Argument \\`exclude\\` is not valid)
  
       * RuntimeError (Argument \\`callables_fname\\` is not valid)
  
       * RuntimeError (Argument \\`full_cname\\` is not valid)
      """
      if not hasattr(__builtin__, "_EXH"):
          set_exh_obj(
              ExHandle(
                  full_cname=full_cname, exclude=exclude, callables_fname=callables_fname
              )
          )
      return get_exh_obj()