code: function _getValidStepsParams(match) {
          var param,
              def = [ "5", "end" ],
              params = def,
              oldIndex = match.index, // we need to store the old match.index to re-set the index afterwards
              originalString = match[0];
  
          if (match) {
              match = match[1].split(",");
          }
  
          if (match) {
              if (match[0]) {
                  param = match[0].replace(/[\s\"']/g, ""); // replace possible trailing whitespace or leading quotes
                  param = _convertToNumber(param);
  
                  // Verify number_of_params is a number
                  // If not, replace it with the default value
                  if (!param.isNumber) {
                      param.value = def[0];
  
                  // Round number_of_params to an integer
                  } else if (param.value) {
                      param.value = Math.floor(param.value);
                  }
  
                  // Verify number_of_steps is >= 1
                  // If not, set them to the default value
                  if (param.value < 1) {
                      param.value = def[0];
                  }
                  params[0] = param.value;
              }
              if (match[1]) {
                  // little autocorrect feature: leading s gets 'start', everything else gets 'end'
                  param = match[1].replace(/[\s\"']/g, ""); // replace possible trailing whitespace or leading quotes
                  param = param.substr(0, 1);
                  if (param === "s") {
                      params[1] = "start";
                  } else {
                      params[1] = "end";
                  }
              }
          }
          params = "steps(" + params.join(", ") + ")";
          params = params.match(STEPS_VALID_REGEX);
  
          if (params) {
              params.index = oldIndex; // re-set the index here to get the right context
              params.originalString = originalString;
              return params;
          }
          return null;
      }
docs: Get valid params for an invalid steps function.
  
  @param {RegExp.match} match (Invalid) matches from stepsMatch()
  @return {?RegExp.match} Valid match or null if the output is not valid