valid_mod_sequence_value?

# File lib/net/imap.rb, line 1678
        def valid_mod_sequence_value?(num)
          # mod-sequence-value  = 1*DIGIT
          #                        ; Positive unsigned 64-bit integer
          #                        ; (mod-sequence)
          #                        ; (1 <= n < 18,446,744,073,709,551,615)
          num >= 1 && num < 18446744073709551615
        end