pub fn member_by_name(&self, name: impl AsRef<str>) -> Result<PackageMetadata<'g>, Error> {
        let name = name.as_ref();
        let id = self
            .inner
            .members_by_name
            .get(name)
            .ok_or_else(|| Error::UnknownWorkspaceName(name.to_string()))?;
        Ok(self.graph.metadata(id).expect("valid package ID"))
    }
Maps the given name to the corresponding workspace member.

Returns an error if the name didn't match any workspace members.
guppy/src/graph/graph_impl.rs