Abstract Python classes

[matveitolochko]

Currently, there is no way to have rust implementations for abstract python classes.

Asked here: PyO3/pyo3#991

Offending code:

class HardwareComponent(_abc.ABC):
    """Represents a basic hardware component."""

    @_abc.abstractproperty
    def uuid(self) -> str:
        """The UUID of this hardware component."""
        ...