class Aws::AssumeRoleCredentials

def refresh
  resp = @client.assume_role(@assume_role_params)
  creds = resp.credentials
  @credentials = Credentials.new(
    creds.access_key_id,
    creds.secret_access_key,
    creds.session_token,
    account_id: parse_account_id(resp)
  )
  @expiration = creds.expiration
end