class SymbolTable(object):
  """Symbol Table for python code."""

  def __init__(self):
    self.symbols = []
    self.enter_scope()
    self.scf_scope = 0
    # reserved key words
    self.insert_symbol('len', 'len', TFRTypes.PY_BUILTIN_FUNC)

  def enter_scope(self, scf_scope=False):
    """Enter a new scope - at function level."""
    self.symbols.append({'types': {}, 'symbols': {}})