private boolean validateFilter(int filter) {
		// Validate the filter.
		if ((filter < IGNORE) || (filter > MERGE)) {
			Msg.error(this, "setFilter: Invalid filter: " + filter);
			return false;
		}
		return true;
	}
validateFilter determines whether or not the filter is one of our valid
 predefiend values.
 Valid filter values are: IGNORE, REPLACE, or MERGE.

@param filter the filter value.
@return true if the filter value is valid.
Ghidra/Features/Base/src/main/java/ghidra/program/util/ProgramMergeFilter.java