code: function gutter(
    math = settings.math,
    columns = settings.columns,
    multiplier = 1
  ) {
    const gutterWidth = _calculateGutter(multiplier);
    const containerWidth = _updateContext(
      typeof columns === "string" ?
      parseInt(columns, 10) :
      columns
    );
  
    if (math === "static") {
      return _staticCalculation(gutterWidth);
    }
  
    if (math === "fluid") {
      return _percent(gutterWidth, containerWidth);
    }
  
    return false;
  }
docs: Output the gutter width
  @param  {string}   math       Type of calculation, "fluid" or "static";
  defaults to global settings
  @param  {number}   columns    The number of columns; changes context
  @param  {number}   multiplier Number to multiply the gutter by
  @return {function}            Function to make calculation