def optional_import(name, feature=None, source=None, comment=None):
 try:
  return __import__(name)
 except ImportError:
  return MissingPackage(name, feature, source, comment)

def optional_import ( name , feature = None , source = None , comment = None ) : try : return __import__ ( name ) except ImportError : return MissingPackage ( name , feature , source , comment )
optionally import package name .