class Net::IMAP::SearchResult

def to_sequence_set; SequenceSet[*self] end

# => Net::IMAP::SequenceSet["1:4,9:10,12"]
.to_sequence_set
Net::IMAP::SearchResult[9, 1, 2, 4, 10, 12, 3, modseq: 123_456]

Converts the SearchResult into a SequenceSet. 
def to_sequence_set; SequenceSet[*self] end