code: def sign(payload, key, headers=None, algorithm=ALGORITHMS.HS256):
      
  
      if algorithm not in ALGORITHMS.SUPPORTED:
          raise JWSError('Algorithm %s not supported.' % algorithm)
  
      encoded_header = _encode_header(algorithm, additional_headers=headers)
      encoded_payload = _encode_payload(payload)
      signed_output = _sign_header_and_claims(encoded_header, encoded_payload, algorithm, key)
  
      return signed_output
docs: Signs a claims set and returns a JWS string.
  
      Args:
          payload (str): A string to sign
          key (str or dict): The key to use for signing the claim set. Can be
              individual JWK or JWK set.
          headers (dict, optional): A set of headers that will be added to
              the default headers.  Any headers that are added as additional
              headers will override the default headers.
          algorithm (str, optional): The algorithm to use for signing the
              the claims.  Defaults to HS256.
  
      Returns:
          str: The string representation of the header, claims, and signature.
  
      Raises:
          JWSError: If there is an error signing the token.
  
      Examples:
  
          >>> jws.sign({'a': 'b'}, 'secret', algorithm='HS256')
          'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhIjoiYiJ9.jiMyrsmD8AoHWeQgmxZ5yq8z0lXS67_QGs52AzC8Ru8'