Sets the connection with the core's open method.

    :param autocommit: the default autocommit state
    :type autocommit: boolean
    :return: self

def open(self, *, autocommit=False):
    """Sets the connection with the core's open method.

    :param autocommit: the default autocommit state
    :type autocommit: boolean
    :return: self
    """
    if self.connection is not None:
      raise Exception("Connection already set")
    self.connection = self.core.open()
    self.autocommit = autocommit
    if self._search_path:
      self._configure_connection(
        "search_path",
        self._search_path)
    return self