whole_func_string: function normalizeKeys (keys, json) {
    Object.keys(json)
      .filter(k => keys.includes(k))
      .forEach(k => {
        json[k] = normalize(json[k])
      })
  
    return json
  }
func_code_string: function normalizeKeys (keys, json) {
    Object.keys(json)
      .filter(k => keys.includes(k))
      .forEach(k => {
        json[k] = normalize(json[k])
      })
  
    return json
  }
func_documentation_string: TODO: this should probably be done as a custom tag processor with xml2js.