code: function isArgumentByLocator (node) {
    if (node.arguments && node.arguments.length && node.arguments[0].type === 'CallExpression') {
      var argument = node.arguments[0]
      if (argument.callee && argument.callee.object && argument.callee.object.name === 'by') {
        return true
      }
    }
    return false
  }
docs: Checks if a given CallExpression node has the argument the "by" expression
  
  @param {ASTNode} node - A node to check.
  @returns {boolean}