private static boolean isAssignable(final Class<?> a, final Class<?> b) {
        if (a == null && b == null) {
            return true;
        }

        if (a == null || b == null) {
            return false;
        }

        return a.isAssignableFrom(b);
    }
Returns true if all the class supplied as a can be assigned
from b
core/src/main/java/com/github/dozermapper/core/util/BridgedMethodFinder.java