undefined method `config' for #<Lob::Configuration about lob-ruby HOT 1 CLOSED

require 'lob'
config = Lob::Configuration.default
config.username = 'XXX'
$lob_config = Lob::ApiClient.new(config)

def send_postcard

  postcardCreate = Lob::PostcardEditable.new({
    description: "Postcard",
    from: "adr_XXXX",
    use_type: "marketing",
    size: "6x9",
    front: "https://XXX-postcard.s3.amazonaws.com/front.pdf",
    back: "https://XXX-postcard.s3.amazonaws.com/back.pdf",
    to: Lob::AddressEditable.new({
      name: "#{self.company} - #{self.name}",
      address_line1: self.line1,
      address_line2: self.line2,
      address_city: self.city,
      address_state: self.state,
      address_zip: self.postal_code,
    }),
  })

  postcardApi = Lob::PostcardsApi.new($lob_config)
  createdPostcard = postcardApi.create(postcardCreate)
end