Can't find any collection named 'fabfile'!

[Sabellus]

invoke.program.parse_collection: No default namespace provided, trying to load one from disk
invoke.loader.find: FilesystemLoader find starting at '/Users/veprev/data/aiochat'
invoke.loader.find: ImportError loading 'fabfile', raising CollectionNotFound
invoke.program.run: Received a possibly-skippable exception: Exit("Can't find any collection named 'fabfile'!")
Can't find any collection named 'fabfile'!
There are errors in the configuration of this machine. Please fix
the following errors and try again:

fabric provisioner:

• ./provision/fabric_provisioner.py could not recognize by fabric.
• common task does not exist.
• database task does not exist.
• nginx task does not exist.
• app task does not exist.
• localserver task does not exist.