module PhonenumberJp
  AREA_CODES: Array[String]
  VERSION: String

  def self.hyphenate: (String | nil) -> (String | nil)
  def self.valid?: (String | nil) -> bool

  private
  def self.split: (String | nil) -> Array[String]
  def self.find_area_code: (String) -> (String | nil)
end