**Purpose of NullMediaItem**

The NullMediaItem class represents the absence of media (image, audio, or video) in a way that avoids special-case handling elsewhere in the code.

It follows the Null Object Pattern
, which provides a default behavior for "no object" cases, eliminating the need for repetitive if media is not None or if media: checks in templates or logic.

**Why use it?**

Without NullMediaItem:


{{{#!python
if question.media:
    for m in question.media:
        if m.type == "image":
            ...
}}}



With NullMediaItem:


{{{#!python
for m in question.media:
    html += m.to_html()
}}}



→ no conditional logic needed – every MediaItem, even the null variant, understands how to behave.

**Behavior of NullMediaItem**
|| Method ||	Behavior ||
||type() ||	Returns "none" ||
|| to_dict() ||	Returns empty {} or None ||
|| to_html() ||	Returns "" (empty string) ||

**When is it used?**

You can attach one or more NullMediaItem()s to a Question instead of using None, [], or omitting the field entirely.

For example:


{{{|!python
question = TextQuestion(
    qid="q1",
    text="What is your name?",
    media=[NullMediaItem()]
)
}}}

This way, the rendering pipeline stays uniform, regardless of whether media is present or not.

**Benefits**

- Simplifies templates and rendering logic

- Eliminates null checks in UI code

- Makes polymorphism clean and consistent

- Encourages Tell, Don't Ask design (don’t ask “do you have media?”, just tell media to render itself)