Create POS resource

        Arguments:
            name:
                Human-readable name of the POS, used for displaying payment
                request origin to end user
            pos_type:
                POS type
            location:
                Merchant location
            pos_id:
                The ID of the POS that is to be created. Has to be unique for
                the merchant

def create_pos(self, name, pos_type,
                   pos_id, location=None):
        """Create POS resource

        Arguments:
            name:
                Human-readable name of the POS, used for displaying payment
                request origin to end user
            pos_type:
                POS type
            location:
                Merchant location
            pos_id:
                The ID of the POS that is to be created. Has to be unique for
                the merchant
        """
        arguments = {'name': name,
                     'type': pos_type,
                     'id': pos_id,
                     'location': location}
        return self.do_req('POST', self.merchant_api_base_url + '/pos/', arguments).json()