def create_serializer(cls, format):
'''create instance of serializer from two classes'''
try:
FormatSerializerCls = serializers.get_serializer(format)
except serializers.SerializerDoesNotExist:
raise Exception("Unknown serialization format: %s" % format)
SerializerCls = type('GitVersionSerializer', (
cls, FormatSerializerCls), {})
return SerializerCls()