code: public static function GESTEP($number, $step = 0)
      {
          $number = Functions::flattenSingleValue($number);
          $step = Functions::flattenSingleValue($step);
  
          return (int) ($number >= $step);
      }
docs: GESTEP.
  
  Excel Function:
  GESTEP(number[,step])
  
  Returns 1 if number >= step; returns 0 (zero) otherwise
  Use this function to filter a set of values. For example, by summing several GESTEP
  functions you calculate the count of values that exceed a threshold.
  
  @param float $number the value to test against step
  @param float $step The threshold value.
  If you omit a value for step, GESTEP uses zero.
  
  @return int