<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def open(cls, typename):
 		"""Create an OMAPI open message with given typename. 		@type typename: bytes 		@rtype: OmapiMessage 		"""

		return cls(opcode=OMAPI_OP_OPEN, message=[(b"type", typename)], tid=-1)