code: def is_token_revoked(decoded_token):
      
      jti = decoded_token['jti']
      try:
          token = TokenBlacklist.query.filter_by(jti=jti).one()
          return token.revoked
      except NoResultFound:
          return True
docs: Checks if the given token is revoked or not. Because we are adding all the
      tokens that we create into this database, if the token is not present
      in the database we are going to consider it revoked, as we don't know where
      it was created.