def replace_values old_values, new_value
      old_values = [old_values] unless old_values.is_a? Array
      rename_hash = old_values.map { |v| [v, new_value] }.to_h
      rename_categories rename_hash
    end
def replace_values old_values, new_value
      old_values = [old_values] unless old_values.is_a? Array
      rename_hash = old_values.map { |v| [v, new_value] }.to_h
      rename_categories rename_hash
    end
Replaces specified values with a new value
 @param [Array] old_values array of values to replace
 @param [object] new_value new value to replace with
 @note It performs the replace in place.
 @return [Daru::Vector] Same vector itself with values
   replaced with new value
 @example
   dv = Daru::Vector.new [1, 2, :a, :b]
   dv.replace_values [:a, :b], nil
   dv
   # =>
   # #<Daru::Vector:19903200 @name = nil @metadata = {} @size = 4 >
   #     nil
   #   0   1
   #   1   2
   #   2 nil
   #   3 nil