code: @SuppressWarnings({"WeakerAccess", "unused"}) // For library users
      public Searcher removeNumericRefinement(@NonNull String attribute) {
          return removeNumericRefinement(new NumericRefinement(attribute, NumericRefinement.OPERATOR_UNKNOWN, NumericRefinement.VALUE_UNKNOWN));
      }
docs: Removes any numeric refinements relative to a specific attribute for the next queries.
  
  @param attribute the attribute that may have a refinement.
  @return this {@link Searcher} for chaining.