class_docstr: Enum to filter requested experiment types.
class_docstr_tok: ["Enum","to","filter","requested","experiment","types","."]
code: def to_proto(cls, view_type):
      if view_type == cls.ACTIVE_ONLY:
          return service_pb2.ACTIVE_ONLY
      elif view_type == cls.DELETED_ONLY:
          return service_pb2.DELETED_ONLY
      elif view_type == cls.ALL:
          return service_pb2.ALL
      raise ValueError(f"Unexpected view_type: {view_type}")
  
imports: from mlflow.protos import service_pb2
label_desc: Use image node_id 3 for calling the ViewType obj's underlying member method code with example usage: obj.to_proto(cls, view_type) and returns: service_pb2, service_pb2, service_pb2