# E4086

The labels are required by this function, but not supplied.

Sometimes this error occurs when you mistakenly treat a labelled argument as a
positional argument. There are some common functions that require labelled
arguments, such as:

- `@test.snapshot`. Remember to supply `filename` as a labelled argument.
- `@test.inspect`. Remember to supply `content` as a labelled argument.

## Erroneous example

```{literalinclude} /sources/error_codes/4086_error/top.mbt
:language: moonbit
```

## Suggestion

Check the signature of the function and provide the correct labelled argument.

```{literalinclude} /sources/error_codes/4086_fixed/top.mbt
:language: moonbit
```