# The error `modal.wheel`

**environment**: something the run needs is missing or different where it runs (a package, a file, a device, the network): the error names what to install, fetch or attach.

Where MIME gives it, with what its message says happened and what its action says to do (`{…}` is filled in from the experiment):

- in `mime/env/_modal_script.py`:
  - what happened: `PyPI gives no record of {…} {…} ({…})`
  - what to do: `write the script where PyPI can be reached, or, before a release, pass --checkout`
- in `mime/env/_modal_script.py`:
  - what happened: `PyPI lists {…} universal wheels of {…} {…}, not one`
  - what to do: `pass --checkout to build the wheel from a checkout of MIME`

Reading an error and reaching its full traceback: [reading an error](../reading_errors.md). Every code: [the index](index.md).