# File lib/json/jwt.rb, line 18
    def initialize(claims = {})
      @content_type = 'application/jwt'
      self.typ = :JWT
      self.alg = :none
      [:exp, :nbf, :iat].each do |key|
        claims[key] = claims[key].to_i if claims[key]
      end
      update claims
    end