def on_self
      scope  = current_scope
      method = scope.lookup(scope.method_call_type, 'self')

      push_value(method.return_value)
    end
def on_self
      scope  = current_scope
      method = scope.lookup(scope.method_call_type, 'self')

      push_value(method.return_value)
    end
Pushes the value of `self` onto the current stack.