public boolean remove(@CheckForNull Object o) {
      if (o instanceof Entry) {
        Entry<?, ?> entry = (Entry<?, ?>) o;
        if (unfiltered.containsKey(entry.getKey())
            // if this holds, then we know entry.getKey() is a K
            && keyPredicate.apply((K) entry.getKey())) {
          return unfiltered.remove(entry.getKey(), entry.getValue());
        }
      }
      return false;
    }
  }

    public boolean remove(@CheckForNull Object o) {
      if (o instanceof Entry) {
        Entry<?, ?> entry = (Entry<?, ?>) o;
        if (unfiltered.containsKey(entry.getKey())
            // if this holds, then we know entry.getKey() is a K
            && keyPredicate.apply((K) entry.getKey())) {
          return unfiltered.remove(entry.getKey(), entry.getValue());
        }
      }
      return false;
    }
  }