code: def _pattern(self, base):
          
          rows = self._rows(base.get(ROWS, []))
          self._finish_inheritance()
          self._finish_instructions()
          self._connect_rows(base.get(CONNECTIONS, []))
          id_ = self._to_id(base[ID])
          name = base[NAME]
          return self.new_pattern(id_, name, rows)
docs: Parse a pattern.