public static string GetNumber(this IDataGenerator dataGenerator, int numberOfDigits, bool canStartWithZero = false) { if (canStartWithZero) { return(dataGenerator.GetString(numberOfDigits, numberOfDigits, "0123456789")); } if (numberOfDigits <= 1) { return(dataGenerator.GetString(numberOfDigits, numberOfDigits, "123456789")); } --numberOfDigits; return($"{dataGenerator.GetCharacter("123456789")}{dataGenerator.GetString(numberOfDigits, numberOfDigits, "0123456789")}"); }