$ snapcraft push codetree_0.1.6_amd64.snap
Pushing codetree_0.1.6_amd64.snap
Preparing to push '/home/mthaddon/repos/codetree/codetree/codetree_0.1.6_amd64.snap' to the store.
Pushing codetree_0.1.6_amd64.snap [============================================================================================================================================================================================================================================] 100%
Processing...|                                                                                                                                                                                                                                                                       
Error while processing...
The store was unable to accept this snap.
  - __all__: The upload does not appear to be a valid package.