lib/hijri_umm_alqura.rb
def + (n)
      case n
      when Numeric then  
        j_date = jd + n * 1 
        result = HijriUmmAlqura.jd(j_date)
        return result
      end
      raise TypeError, 'expected numeric'
    end
def + (n)
      case n
      when Numeric then  
        j_date = jd + n * 1 
        result = HijriUmmAlqura.jd(j_date)
        return result
      end
      raise TypeError, 'expected numeric'
    end
comparison operator
 return hijri date plus n days