code: function _validateCubicBezierParams(match) {
          var x1 = _convertToNumber(match[1]),
              y1 = _convertToNumber(match[2]),
              x2 = _convertToNumber(match[3]),
              y2 = _convertToNumber(match[4]);
  
          // Verify all params are numbers
          if (!x1.isNumber || !y1.isNumber || !x2.isNumber || !y2.isNumber) {
              return false;
          }
  
          // Verify x params are in 0-1 range
          if (x1.value < 0 || x1.value > 1 || x2.value < 0 || x2.value > 1) {
              return false;
          }
  
          return true;
      }
docs: Validate cubic-bezier function parameters that are not already validated by regex:
  
  @param {RegExp.match} match  RegExp Match object with cubic-bezier function parameters
  in array positions 1-4.
  @return {boolean} true if all parameters are valid, otherwise, false