def get_api_key_with_prefix(self, identifier):
if self.api_key.get(identifier) and self.api_key_prefix.get(identifier):<EOL><INDENT>return self.api_key_prefix[identifier] + '<STR_LIT:U+0020>' + self.api_key[identifier]<EOL><DEDENT>elif self.api_key.get(identifier):<EOL><INDENT>return self.api_key[identifier]<EOL><DEDENT>
Gets API key (with prefix if set).

:param identifier: The identifier of apiKey.
:return: The token for api key authentication.