function getIteratee() {
      var result = lodash.iteratee || iteratee;
      result = result === iteratee ? baseIteratee : result;
      return arguments.length ? result(arguments[0], arguments[1]) : result;
    }
Gets the appropriate "iteratee" function. If `_.iteratee` is customized,
this function returns the custom method, otherwise it returns `baseIteratee`.
If arguments are provided, the chosen function is invoked with them and
its result is returned.

@private
@param {*} [value] The value to convert to an iteratee.
@param {number} [arity] The arity of the created iteratee.
@returns {Function} Returns the chosen function or its result.