code: def as_string(self, forsigning=False):
  		
  		ret = OutBuffer()
  		self.serialize(ret, forsigning)
  		return ret.getvalue()
docs: >>> len(OmapiMessage().as_string(True)) >= 24
  		True
  
  		@type forsigning: bool
  		@rtype: bytes
  		@raises OmapiSizeLimitError: