class_docstr: Internal Var (with '__' prefix and won't appear in SSA) will ALWAYS have
  `sym_val == builtin.unknown`. InternalVar are constructed by builder only.
  
  Comment: Internal Var can be used to represent diverse types such as enum
  type `DataType.FLOAT32`.
class_docstr_tok: ["Internal","Var","(","with","'__","'","prefix","and","wo","n't","appear","in","SSA",")","will","ALWAYS","have","`","sym_val","==","builtin.unknown","`",".","InternalVar","are","constructed","by","builder","only",".","Comment",":","Internal","Var","can","be","used","to","represent","diverse","types","such","as","enum","type","`","DataType.FLOAT32","`","."]
code: def __init__(self, val, name=None):
      super().__init__(
          name=name, sym_type=types.unknown, sym_val=types.unknown(val)
      )
  
imports: from typing import Optional, Union
  from coremltools.converters.mil.mil import types
  from coremltools.converters.mil.mil.types import builtin_to_string
  from coremltools.converters.mil.mil.types.symbolic import any_symbolic
label_desc: Use image node_id 1 to create a new InternalVar object from inherited base classes: Var with example: obj = InternalVar(val, name)