Getting only direct child pages in WordPress with get_pages

I am trying to fetch all direct children of a page. But I am getting all children and grand children as well. Any ideas?

PHP Source:

$args = array( 
        'child_of' => $post->ID, 
        'parent ' => $post->ID,
        'hierarchical' => 0,
        'sort_column' => 'menu_order', 
        'sort_order' => 'asc'
);
$mypages = get_pages( $args );

foreach( $mypages as $post )
{

$post_tempalte = the_page_template_part();

get_template_part( 'content' , $post_tempalte );
}

My $args should be correct according to the documentation, but it’s totally ignoring parent and hierarchical.

My page structure is as follows:

Parent
-Child 1
-Child 2
–Child 1 to child 2
–Child 2 to child 2
-Child 3

And I only want to get child 1, child 2 and child 3.

Please check the parameter ‘parent’. It seems there is a space after the name.