code: def add_functions(self, names, functions):
          
          if isinstance(names, string_types):
              names = [names]
              functions = [functions]
          if len(functions) != len(names):
              raise ValueError("number of provided names must be same as number "
                               "of functions")
          self._functionlib.update(dict(zip(names, functions)))
docs: Adds the given functions to the function library.
  
          Functions are added to this instance of the array; all copies of
          and slices of this array will also have the new functions included.
  
          Parameters
          ----------
          names : (list of) string(s)
              Name or list of names of the functions.
          functions : (list of) function(s)
              The function(s) to call.