gnus-remove-if-not
gnus-remove-if-not is a compiled Lisp function in `gnus-util.el
'.
(gnus-remove-if-not PREDICATE SEQUENCE &optional HASH-TABLE-P)
Return a copy of SEQUENCE with all items not satisfying PREDICATE removed.
SEQUENCE should be a list, a vector, or a string. Returns always a list.
If HASH-TABLE-P is non-nil, regards SEQUENCE as a hash table.