code: def hooked_by(self, addr):
          
  
          if not self.is_hooked(addr):
              l.warning("Address %s is not hooked", self._addr_to_str(addr))
              return None
  
          return self._sim_procedures[addr]
docs: Returns the current hook for `addr`.
  
          :param addr: An address.
  
          :returns:    None if the address is not hooked.