atomref.errors

atomref distinguishes missing scientific data from invalid configuration or malformed packaged data. Ordinary lookup misses use None or a missing LookupResult; catchable operational failures use the exceptions below.

The exceptions are imported from atomref.errors and are deliberately not re-exported from the top-level package.

atomref.errors

Catchable exceptions raised by atomref submodules.

AtomrefError

Bases: Exception

Base class for package-defined operational errors.

Notes

The exception classes are documented from atomref.errors but are not re-exported from the top-level atomref namespace.

DatasetError

Bases: AtomrefError

Report an unavailable, unknown, or malformed dataset.

Examples:

Catch this exception when a user-selected dataset identifier may be unavailable:

>>> from atomref.errors import DatasetError
>>> try:
...     raise DatasetError("unknown dataset")
... except DatasetError:
...     pass

MissingValueError

Bases: AtomrefError

Report that an operation requires an unavailable reference value.

Notes

Ordinary lookup functions generally represent missing scientific data with None or a missing LookupResult rather than raising this exception.

PolicyError

Bases: AtomrefError

Report invalid policy configuration or transfer resolution.

Examples:

This includes incompatible radii kinds, invalid transfer controls, and cyclic nested policies. Callers that accept user-authored policies can catch PolicyError to distinguish those failures from missing values.