class ActiveSupport::NumberHelper::NumberToPhoneConverter

def convert_without_area_code(number)
  default_pattern = /(\d{0,3})(\d{3})(\d{4})$/
  number.gsub!(regexp_pattern(default_pattern),
               "\\1#{delimiter}\\2#{delimiter}\\3")
  number.slice!(0, 1) if start_with_delimiter?(number)
  number
end