Builds the Signature of the SAML Request.

        :param saml_request: The SAML Request
        :type saml_request: string

        :param relay_state: The target URL the user should be redirected to
        :type relay_state: string

        :param sign_algorithm: Signature algorithm method
        :type sign_algorithm: string

def build_request_signature(self, saml_request, relay_state, sign_algorithm=OneLogin_Saml2_Constants.RSA_SHA1):
        """
        Builds the Signature of the SAML Request.

        :param saml_request: The SAML Request
        :type saml_request: string

        :param relay_state: The target URL the user should be redirected to
        :type relay_state: string

        :param sign_algorithm: Signature algorithm method
        :type sign_algorithm: string
        """
        return self.__build_signature(saml_request, relay_state, 'SAMLRequest', sign_algorithm)