def gen_sign_user_opts from
    account = AccountManager.account_for from
    account ||= AccountManager.default_account
    if !account.gpgkey.nil?
      opts = {:signer => account.gpgkey}
    elsif AccountManager.user_emails.length == 1
      # only one account
      opts = {}
    else
      opts = {:signer => from}
    end
    opts
  end
def gen_sign_user_opts from
    account = AccountManager.account_for from
    account ||= AccountManager.default_account
    if !account.gpgkey.nil?
      opts = {:signer => account.gpgkey}
    elsif AccountManager.user_emails.length == 1
      # only one account
      opts = {}
    else
      opts = {:signer => from}
    end
    opts
  end
logic is:
 if    gpgkey set for this account, then use that
 elsif only one account,            then leave blank so gpg default will be user
 else                                    set --local-user from_email_address
 NOTE: multiple signers doesn't seem to work with gpgme (2.0.2, 1.0.8)