code: def import_module(module_name):
      
      try:
          return importlib.import_module(module_name)
      except ImportError as err:
          raise UnknownModuleError(str(err))
docs: Given a dotted Python path, imports & returns the module.
  
      If not found, raises ``UnknownModuleError``.
  
      Ex::
  
          mod = import_module('random')
  
      :param module_name: The dotted Python path
      :type module_name: string
  
      :returns: module