docs: def qteDefVar(self, varName: str, value, module=None, doc: str=None):
          """
          Define and document ``varName`` in an arbitrary name space.
  
          If ``module`` is **None** then ``qte_global`` will be used.
  
          .. warning: If the ``varName`` was already defined in
             ``module`` then its value and documentation are overwritten
             without warning.
  
          |Args|
  
          * ``varName`` (**str**): variable name.
          * ``value`` (**object**): arbitrary data to store.
          * ``module`` (**Python module**): the module in which the
            variable should be defined.
          * ``doc`` (**str**): documentation string for variable.
  
          |Returns|
  
          **bool**: **True** if ``varName`` could be defined in
            ``module``.
  
          |Raises|
  
          * **QtmacsArgumentError** if at least one argument has an invalid type.
          """
          # Use the global name space per default.
          if module is None:
              module = qte_global
  
          # Create the documentation dictionary if it does not exist
          # already.
          if not hasattr(module, '_qte__variable__docstring__dictionary__'):
              module._qte__variable__docstring__dictionary__ = {}
  
          # Set the variable value and documentation string.
          setattr(module, varName, value)
          module._qte__variable__docstring__dictionary__[varName] = doc
          return True