Yields peptides from generator as long as their sequence is not found in
    known search space dict. Useful for excluding peptides that are found in
    e.g. ENSEMBL or similar

def filter_known_searchspace(elements, seqtype, lookup, ns, ntermwildcards,
                             deamidation):
    """Yields peptides from generator as long as their sequence is not found in
    known search space dict. Useful for excluding peptides that are found in
    e.g. ENSEMBL or similar"""
    for element in elements:
        seq_is_known = False
        for seq in get_seqs_from_element(element, seqtype, ns, deamidation):
            if lookup.check_seq_exists(seq, ntermwildcards):
                seq_is_known = True
                break
        if seq_is_known:
            formatting.clear_el(element)
        else:
            yield formatting.string_and_clear(element, ns)