@property<EOL><INDENT>def _default_headers(self):<DEDENT>
headers = {<EOL>"<STR_LIT>": '<STR_LIT>'.format(self.api_key),<EOL>"<STR_LIT>": self.useragent,<EOL>"<STR_LIT>": '<STR_LIT:application/json>'<EOL>}<EOL>if self.impersonate_subuser:<EOL><INDENT>headers['<STR_LIT>'] = self.impersonate_subuser<EOL><DEDENT>return headers<EOL>
Set the default header for a Twilio SendGrid v3 API call