code: def add_request_signature(self, request_data, sign_algorithm=OneLogin_Saml2_Constants.RSA_SHA1):
          
          return self.__build_signature(request_data, 'SAMLRequest', sign_algorithm)
docs: Builds the Signature of the SAML Request.
  
          :param request_data: The Request parameters
          :type request_data: dict
  
          :param sign_algorithm: Signature algorithm method
          :type sign_algorithm: string