class_docstr: A functional visitor over Type.
  
  The default behavior recursively traverses the AST
  and reconstructs the AST.
code: def visit_type_var(self, tv):
      return TypeVar(tv.name_hint, tv.kind)
  
imports: from .ty import TypeVar, IncompleteType, TensorType, FuncType, TupleType, TypeRelation, RefType, GlobalTypeVar, TypeCall
  from .adt import TypeData
label_desc: Use image node_id 1 for calling the TypeMutator obj's underlying member method code with example usage: obj.visit_type_var(tv) and returns: TypeVar