def from_dict(package_dict):
if not package_dict:
return None
package_ = Package(None)
package_.id = package_dict.get('id')
package_.schema_version = package_dict.get('schema_version')
package_.timestamp = datetime.datetime.strptime(package_dict.get('timestamp'), "%Y-%m-%dT%H:%M:%S.%f")
package_.malware_subjects = MalwareSubjectList.from_list(package_dict.get('malware_subjects', []))
package_.grouping_relationships = GroupingRelationshipList.from_list(package_dict.get('grouping_relationships', []))
return package_
