public function appendTo($key, $value)
    {
        if (!$this->offsetExists($key)) {
            $this[$key] = [$value];
            return;
        }
        $old_value = $this[$key];
        if (!is_array($old_value)) {
            $old_value = [$old_value];
        }
        if (is_array($value)) {
            $old_value = array_merge($old_value, $value);
        } else {
            $old_value[] = $value;
        }
        $this[$key] = $old_value;
    }
public function appendTo($key, $value)
    {
        if (!$this->offsetExists($key)) {
            $this[$key] = [$value];
            return;
        }
        $old_value = $this[$key];
        if (!is_array($old_value)) {
            $old_value = [$old_value];
        }
        if (is_array($value)) {
            $old_value = array_merge($old_value, $value);
        } else {
            $old_value[] = $value;
        }
        $this[$key] = $old_value;
    }
public function appendTo ( $ key , $ value ) { if ( ! $ this -> offsetExists ( $ key ) ) { $ this [ $ key ] = [ $ value ] ; return ; } $ old_value = $ this [ $ key ] ; if ( ! is_array ( $ old_value ) ) { $ old_value = [ $ old_value ] ; } if ( is_array ( $ value ) ) { $ old_value = array_merge ( $ old_value , $ value ) ; } else { $ old_value [ ] = $ value ; } $ this [ $ key ] = $ old_value ; }
Append to an already stored array.

@param string $key the key under which we have previously stored data.
@param mixed $value the value which we want to append to the existing data.

Note, that the following will not work:
<code>
$container['foo'] = array('bar','baz');
$container['foo'][] = 42;
</code>

See also: https://github.com/silexphp/Pimple/issues/149
<quote>
fabpot commented on Jul 15, 2014
To be more precise, Pimple stores parameters but it should have
no knowledge of the parameter value; Pimple just stores what you give it.
</quote>
Append to an already stored array .