If I am at a zsh prompt and I have the current "context" (partially completed command-line command)

```
% man gr_
        ^ here I have used _ to  represent the cursor 

```

If I then invoke the `_complete_help` function ``Ctrl``X```h`

It tells me the context is

```
% man gr_
tags in context :completion::complete:man::
    manuals  (_man)

```

If I am reading this output correctly - I can see there is a completer function `_man` that is capable of listing all the known man pages - which would be invoked if I hit the `Tab` key at this point.  

My question is, can I call the `_man` completer function manually? rather than having `_man` being invoked by compsys (which itself is invoked by `Tab`)?

I have tried using the zle minibuffer `<Esc>x` , then type `_man<Enter>` but I think the mini-buffer is only capable of understanding zle commands, not executing general functions.