code: function getOpeningParenOfParams(node, sourceCode) {
      return node.id
          ? sourceCode.getTokenAfter(node.id, isOpeningParenToken)
          : sourceCode.getFirstToken(node, isOpeningParenToken);
  }
docs: Gets the `(` token of the given function node.
  
  @param {ASTNode} node - The function node to get.
  @param {SourceCode} sourceCode - The source code object to get tokens.
  @returns {Token} `(` token.