def add_collection(self, property_name, use_context=True):
if self.has_property(property_name):<EOL><INDENT>err = '<STR_LIT>'<EOL>raise PropertyExists(err.format(property_name))<EOL><DEDENT>prop = CollectionProperty(use_context=bool(use_context))<EOL>self.collections[property_name] = prop<EOL>return prop<EOL>
Add collection property to schema
:param property_name: str, property name
:param property_name: str, property name
:return: shiftschema.property.CollectionProperty