function unary(func) {
      return ary(func, 1);
    }
Creates a function that accepts up to one argument, ignoring any
additional arguments.

@static
@memberOf _
@since 4.0.0
@category Function
@param {Function} func The function to cap arguments for.
@returns {Function} Returns the new capped function.
@example

_.map(['6', '8', '10'], _.unary(parseInt));
// => [6, 8, 10]