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': {}})

@OptIn(ExperimentalContracts::class)
internal
inline fun AnalysisContext.withScope(scope: AnalysisScope, action: () -> Unit) {
    contract {
        callsInPlace(action, InvocationKind.EXACTLY_ONCE)
    }
    enterScope(scope)
    try {
        action()
    } finally {
        leaveScope(scope)
    }
}


internal
fun checkIsAssignable(valueType: DataType, isAssignableTo: DataType): Boolean = when (isAssignableTo) {

    private
    val typeRefContext = SchemaTypeRefContext(schema)

    override fun resolveRef(dataTypeRef: DataTypeRef): DataType = typeRefContext.resolveRef(dataTypeRef)

    fun enterScope(newScope: AnalysisScope) {
        mutableScopes.add(newScope)
    }