properties.py 文件源码

def versions(
        self,
        versions  # type: Optional[Sequence[Union[str, Version]]]
    ):
        # type: (...) -> Optional[Union[Mapping[str, Optional[Property]], Set[Union[str, Number]]]]
        if versions is not None:
            if isinstance(versions, (str, Number, meta.Version)):
                versions = (versions,)
            if isinstance(versions, Iterable):
                versions = tuple(
                    (v if isinstance(v, meta.Version) else meta.Version(v))
                    for v in versions
                )
            else:
                raise TypeError(
                    '``Property.versions`` requires a sequence of version strings or ' +
                    '``serial.properties.metadata.Version`` instances, not ' +
                    '``%s``.' % type(versions).__name__
                )
        self._versions = versions