class Mailgun::Client

def perform_data_validation(working_domain, data)
  message = data.respond_to?(:message) ? data.message : data
  fail ParameterError.new('Missing working domain', working_domain) unless working_domain
  fail ParameterError.new(
    'Missing `to` recipient, message should contain at least 1 recipient',
    working_domain
  ) if message.fetch('to', []).empty? && message.fetch(:to, []).empty?
  fail ParameterError.new(
    'Missing a `from` sender, message should contain at least 1 `from` sender',
    working_domain
  ) if message.fetch('from', []).empty? && message.fetch(:from, []).empty?
end