code: function getLocation (node, sourceCode) {
    if (node.type === 'ArrowFunctionExpression') {
      return sourceCode.getTokenBefore(node.body)
    }
    return node.id || node
  }
docs: Gets a readable location.
  
  - FunctionExpression -> the function name or `function` keyword.
  - ArrowFunctionExpression -> `=>` token.
  
  @param {ASTNode} node - A function node to get.
  @param {SourceCode} sourceCode - A source code to get tokens.
  @returns {ASTNode|Token} The node or the token of a location.