How do I call get_post_meta properly
I'm a bit confused, but if I call `get_post_meta(get_the_ID(), "event", $single = true);` it returns the value for that key, but if I call it this way:

	$event_page_meta = "event";
	
	
	function isEvent()
	{
		return get_post_meta(get_the_ID(), $event_page_meta, $single = true);
	}

it returns Array of all meta. I'm rather unexperienced php-developer (mostly python), but I cannot see any difference between those two calls. 

Can you explain why I cannot extract that key to a variable? 
How do I call get_post_meta properly
===

I'm a bit confused, but if I call `get_post_meta(get_the_ID(), "event", $single = true);` it returns the value for that key, but if I call it this way:

	$event_page_meta = "event";
	
	
	function isEvent()
	{
		return get_post_meta(get_the_ID(), $event_page_meta, $single = true);
	}

it returns Array of all meta. I'm rather unexperienced php-developer (mostly python), but I cannot see any difference between those two calls. 

Can you explain why I cannot extract that key to a variable? 