def get_issuers(self):
issuers = []<EOL>message_issuer_nodes = OneLogin_Saml2_Utils.query(self.document, '<STR_LIT>')<EOL>if len(message_issuer_nodes) > <NUM_LIT:0>:<EOL><INDENT>if len(message_issuer_nodes) == <NUM_LIT:1>:<EOL><INDENT>issuers.append(OneLogin_Saml2_Utils.element_text(message_issuer_nodes[<NUM_LIT:0>]))<EOL><DEDENT>else:<EOL><INDENT>raise OneLogin_Saml2_ValidationError(<EOL>'<STR_LIT>',<EOL>OneLogin_Saml2_ValidationError.ISSUER_MULTIPLE_IN_RESPONSE<EOL>)<EOL><DEDENT><DEDENT>assertion_issuer_nodes = self.__query_assertion('<STR_LIT>')<EOL>if len(assertion_issuer_nodes) == <NUM_LIT:1>:<EOL><INDENT>issuers.append(OneLogin_Saml2_Utils.element_text(assertion_issuer_nodes[<NUM_LIT:0>]))<EOL><DEDENT>else:<EOL><INDENT>raise OneLogin_Saml2_ValidationError(<EOL>'<STR_LIT>',<EOL>OneLogin_Saml2_ValidationError.ISSUER_NOT_FOUND_IN_ASSERTION<EOL>)<EOL><DEDENT>return list(set(issuers))<EOL>
Gets the issuers (from message and from assertion)

:returns: The issuers
:rtype: list