<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def close(self, suppress_warning: bool = False) -> None: 		""" 		Close the connection. After this, the connection object becomes invalid. Warns user if called after closing. 		Args: 			suppress_warning:		Suppresses warning message if True (defaults to false) 		"""

		if self._file is None:
			if not suppress_warning:
				# Warn user that they're being paranoid
				# and should clean up their code
				logging.warn("Connection to %s is already closed", self.filename)
		else:
			self._file.close()
			self._file = None
		self.layers = None  # type: ignore
		self.ra = None  # type: ignore
		self.row_attrs = None  # type: ignore
		self.ca = None  # type: ignore
		self.col_attrs = None  # type: ignore
		self.row_graphs = None  # type: ignore
		self.col_graphs = None  # type: ignore
		self.shape = (0, 0)
		self._closed = True