code: def _validate_conn(self, conn):
          
          super(HTTPSConnectionPool, self)._validate_conn(conn)
  
          # Force connect early to allow us to validate the connection.
          if not getattr(conn, 'sock', None):  # AppEngine might not have  `.sock`
              conn.connect()
  
          if not conn.is_verified:
              warnings.warn((
                  'Unverified HTTPS request is being made. '
                  'Adding certificate verification is strongly advised. See: '
                  'https://urllib3.readthedocs.org/en/latest/security.html'),
                  InsecureRequestWarning)
docs: Called right before a request is made, after the socket is created.