@Nullable
  default PyAstExpression getTarget() {
    ASTNode[] children = getNode().getChildren(null);
    boolean foundAs = false;
    for (ASTNode child : children) {
      if (child.getElementType() == PyTokenTypes.AS_KEYWORD) {
        foundAs = true;
      }
      else if (foundAs && child.getPsi() instanceof PyAstExpression) {
        return (PyAstExpression)child.getPsi();
      }
    }
    return null;
  }
@Nullable
  default PyAstExpression getTarget()