boolean contains(long key) {
			return cacheMap.containsKey(key);
		}
Determine if cache contains datatype pair equivalence entry

@param key datatype identity pair (see
           {@link DataTypeManagerDB#getEquivalenceKey(DataTypeDB, DataType)}
@return true if cache contains specified datatype identify pair
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/data/DataTypeManagerDB.java