public @Nullable V remove(@Nullable Object key) {
        V value = get(key);
        if (value != null) {
          // it's definitely in the map, so the cast and requireNonNull are safe
          @SuppressWarnings("unchecked")
          Range<K> range = (Range<K>) requireNonNull(key);
          TreeRangeMap.this.remove(range);
          return value;
        }
        return null;
      }

      @Override

      checkState(
          state == FAILED,
          "failureCause() is only valid if the service has failed, service is %s",
          state);
      // requireNonNull is safe because the constructor requires a non-null cause with state=FAILED.
      return requireNonNull(failure);
    }
  }

 * limitations under the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.Objects.requireNonNull;

import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.concurrent.LazyInit;
import java.io.Serializable;

   */

  private Object requireTable() {
    return requireNonNull(table);
  }

  private int[] requireEntries() {
    return requireNonNull(entries);
  }

  private @Nullable Object[] requireKeys() {
    return requireNonNull(keys);
  }

  private @Nullable Object[] requireValues() {
    return requireNonNull(values);
  }

  /*

      class LocalClass<T> {}
      Class<?> subclass = new LocalClass<String>() {}.getClass();
      // requireNonNull is safe because we're examining a type that's known to have a superclass.
      ParameterizedType parameterizedType =
          requireNonNull((ParameterizedType) subclass.getGenericSuperclass());
      for (ClassOwnership behavior : ClassOwnership.values()) {

      Object key = requireNonNull(stream.readObject());
      int valueCount = stream.readInt();
      if (valueCount <= 0) {
        throw new InvalidObjectException("Invalid value count " + valueCount);
      }

      ImmutableList.Builder<Object> valuesBuilder = ImmutableList.builder();
      for (int j = 0; j < valueCount; j++) {
        valuesBuilder.add(requireNonNull(stream.readObject()));
      }

    }

    @Override
    public void remove() {
      valueIterator.remove();
      /*
       * requireNonNull is safe because we've already initialized `collection`. If we hadn't, then
       * valueIterator.remove() would have failed.
       */
      if (requireNonNull(collection).isEmpty()) {
        keyIterator.remove();
      }
      totalSize--;
    }
  }

  /**

       * entry objects that cannot be safely reused.
       */
      switch (size) {
        case 0:
          return of();
        case 1:
          // requireNonNull is safe because the first `size` elements have been filled in.
          Entry<K, V> onlyEntry = requireNonNull(entries[0]);
          return of(onlyEntry.getKey(), onlyEntry.getValue());
        default:
          break;
      }

      stream.defaultReadObject();
      factory = (Supplier<? extends Collection<V>>) requireNonNull(stream.readObject());
      Map<K, Collection<V>> map = (Map<K, Collection<V>>) requireNonNull(stream.readObject());
      setMap(map);
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  /**

      stream.defaultReadObject();
      factory = (Supplier<? extends Collection<V>>) requireNonNull(stream.readObject());
      Map<K, Collection<V>> map = (Map<K, Collection<V>>) requireNonNull(stream.readObject());
      setMap(map);
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  /**