_ (dest, src) {
    utils.forOwn(src, function (value, key) {
      if (
        key &&
        dest[key] === undefined &&
        !utils.isFunction(value) &&
        key.indexOf('_') !== 0
      ) {
        dest[key] = value
      }
    })
  }
Shallow copy properties that meet the following criteria from `src` to
`dest`:

- own enumerable
- not a function
- does not start with "_"

@method utils._
@param {object} dest Destination object.
@param {object} src Source object.
@private
@since 3.0.0