https://github.com/savastakan/dnmso#Gap
Class 'Gap; an m/z range that couldn't be assigned an AminoAcid or a ModAminoAcid. '

Class [owl:Class]

For de novo sequencing results, it often occurs that some parts of the sequence cannot be supported with much evidence. Instead of storing an arbitrary subsequence, a gap of appropriate m/z range (monoisotopic mass) can be inserted in the Sequence. The gapValue represents the size of the gap and is obligatory.

Gap; an m/z range that couldn't be assigned an AminoAcid or a ModAminoAcid.

gapValue; m/z range without sequence information. exactly 1

SequenceElement; an element of the predicted sequence (AminoAcid, ModAminoAcid, Gap).