code: public <T> Key<T> insert(final String collection, final T entity, final WriteConcern wc) {
          return insert(getCollection(collection), ProxyHelper.unwrap(entity), new InsertOptions().writeConcern(wc));
      }
docs: Inserts an entity in to the database
  
  @param collection the collection to query against
  @param entity     the entity to insert
  @param wc         the WriteConcern to use when deleting
  @param <T>        the type of the entities
  @return the key of entity