Moves the email to the folder specified by the folder parameter.

        Args:
            folder: A string containing the folder ID the message should be moved to, or a Folder instance

def move_to(self, folder):
        """Moves the email to the folder specified by the folder parameter.

        Args:
            folder: A string containing the folder ID the message should be moved to, or a Folder instance

        """
        if isinstance(folder, Folder):
            self.move_to(folder.id)
        else:
            self._move_to(folder)