Wrong condition in removeGranularity method

There are wrong condition in removeGranularity method, it doesnt work if I want to remove granularity with key '0' in granularity array.

Method code:

  public function removeGranularity($g) {
    if ($key = array_search($g, $this->granularity)) {
      unset($this->granularity[$key]);
    }
  }

Test case:

$this->granularity = array(
    0 => hour,
    1 => minute,
    2 => second
);

This method will not work If I want to remove 'hour' element:

  $this->removeGranularity('hour');

because key of 'hour' element is '0', and ($key = array_search($g, $this->granularity)) condition is false.