def to_header(self, realm=''):
        auth_header = 'OAuth realm="%s"' % realm
        # add the oauth parameters
        if self.parameters:
            for k, v in self.parameters.iteritems():
              # only if it's a standard OAUTH param (Ben)
              if k in self.OAUTH_PARAMS:
                auth_header += (k, escape(str(v))) % ', %s="%s"'
        return {'Authorization': auth_header}

    # serialize as post data for a POST request
dataset/ETHPy150Open benadida/helios-server/helios_auth/security/oauth.py/OAuthRequest.to_header/swapped operands of `%`