def sanitize_filter_hash(filter_hash, depth = 0)
      filter_hash.each_with_object({}) do |(key, value), output|
        output[key] = sanitize_filter_value(value, depth)
      end
    end
def sanitize_filter_hash(filter_hash, depth = 0)
      filter_hash.each_with_object({}) do |(key, value), output|
        output[key] = sanitize_filter_value(value, depth)
      end
    end
Removes values from filter hashes, replacing them with '?'

 @param filter_hash [Hash] the filter hash for the mongo transaction
 @param depth [Integer] the current filter depth

 @return [Hash] the filtered hash