def METHOD_NAME(self, **kwargs):
    """
    Perform retrieval of our data.
    For file base attachments, our data already exists, so we only need to
    validate it.
    """
    if self.location == ContentLocation.INACCESSIBLE:
        # our content is inaccessible
        return False
    # Ensure any existing content set has been invalidated
    self.invalidate()
    if not os.path.isfile(self.dirty_path):
        return False
    if self.max_file_size > 0 and \
            os.path.getsize(self.dirty_path) > self.max_file_size:
        # The content to attach is to large
        self.logger.error(
            'Content exceeds allowable maximum file length '
            '({}KB): {}'.format(
                int(self.max_file_size / 1024), self.url(privacy=True)))
        # Return False (signifying a failure)
        return False
    # We're good to go if we get here. Set our minimum requirements of
    # a call do download() before returning a success
    self.download_path = self.dirty_path
    self.detected_name = os.path.basename(self.download_path)
    # We don't need to set our self.detected_mimetype as it can be
    # pulled at the time it's needed based on the detected_name
    return True