old_contents: var _ = require('lodash');
  var concat = require('..').concat;
  
  var s1 = [8, 2, 85, 2, 34, 3, 23];
  var s2 = [247, 57, 8, 0, 6, 5, 46, 54, 643];
  var concatS1 = concat(s1);
  
  module.exports = {
      name: 'concat',
      tests: {
          '_.concat': function() {
              _.concat(s1, s2);
          },
          'concat(s1, s2)': function() {
              concat(s1, s2);
          },
          'concat(s1)(s2)': function() {
              concat(s1)(s2);
          },
          'concatS1(s1)': function() {
              concatS1(s2);
          }
      }
  };
  
new_contents: var _ = require('lodash');
  var concat = require('..').concat;
  
  var s1 = [8, 2, 85, 2, 34, 3, 23];
  var s2 = [247, 57, 8, 0, 6, 5, 46, 54, 643];
  var concatS1 = concat(s1);
  
  module.exports = {
      name: 'concat',
      tests: {
          '_.concat': function() {
              _.concat(s1, s2);
          },
          'concat(s1, s2)': function() {
              concat(s1, s2);
          },
          'concat(s1)(s2)': function() {
              concat(s1)(s2);
          },
          'concatS1(s2)': function() {
              concatS1(s2);
          }
      }
  };
  
subject: fix string typo inconsistency with method invocation