code: def ceiling_func(self, addr):
          
  
          try:
              next_addr = self._function_map.ceiling_addr(addr)
              return self._function_map.get(next_addr)
  
          except KeyError:
              return None
docs: Return the function who has the least address that is greater than or equal to `addr`.
  
          :param int addr: The address to query.
          :return:         A Function instance, or None if there is no other function after `addr`.
          :rtype:          Function or None