Finds a single attachment matching the given vendor and conformsTo.
Unlike attachments which returns an array, this method requires exactly one attachment to match.
attachments
Optional vendor and conformsTo to match
vendor
conformsTo
The matching attachment envelope
EnvelopeError if not exactly one attachment matches
Finds a single attachment matching the given vendor and conformsTo.
Unlike
attachmentswhich returns an array, this method requires exactly one attachment to match.