=cut
# some helper routines
+#
+# _bop_recurring_billing: Checks whether this payment should have the
+# recurring_billing flag used by some B:OP interfaces (IPPay, PlugnPay,
+# vSecure, etc.). This works in two different modes:
+# - actual_oncard (default): treat the payment as recurring if the customer
+# has made a payment using this card before.
+# - transaction_is_recur: treat the payment as recurring if the invoice
+# being paid has any recurring package charges.
+
sub _bop_recurring_billing {
my( $self, %opt ) = @_;