For example, could we do:

```ruby
      def filter_params(params_hash, extra_filter_keys = nil)
        filter_keys = (Array(extra_filter_keys) + Raygun.configuration.filter_parameters).map(&:to_s)
 
        # Need to filter nested hash, so filter_params recursively
        params_hash.inject({}) { |result, (k, v)|
          result[k] = case v
          when Hash
            filter_params(v, extra_filter_keys)
          else
            filter_keys.include?(k) ? "[FILTERED]" : v
          end
        }
      end
```