@SuppressWarnings("unchecked")
	private static <T extends DataType> T getAssignableDataType(Category category, String dtName,
			Class<? extends DataType> classConstraint) {
		DataType dt = category.getDataType(dtName);
		if (dt != null &&
			(classConstraint == null || classConstraint.isAssignableFrom(dt.getClass()))) {
			return (T) dt;
		}
		return null;
	}
Get the specified datatype by name and category and return only if its type 
corresponds to an class constraint if specified.
@param <T> A standard interface which extends {@link DataType} (e.g., {@link Structure}).
@param category datatype category to query
@param dtName datatype name
@param classConstraint datatype class constraint (optional, may be null)
@return datatype which corresponds to specified path or null if not found
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/data/DataTypeUtilities.java