Merge branch 'jjardon/warnings_collections' into 'master'

import os

import string

from collections import Mapping, namedtuple

from collections import namedtuple

from collections.abc import Mapping

from ..types import _KeyStrength

from .._exceptions import ArtifactError, ImplError, LoadError, LoadErrorReason

import os

import datetime

from collections import deque, Mapping

from collections import deque

from collections.abc import Mapping

from contextlib import contextmanager

from . import utils

from . import _cachekey

import os

from collections import Mapping

from collections.abc import Mapping

from . import _yaml

from ._exceptions import LoadError, LoadErrorReason

#        Tristan Van Berkom <tristan.vanberkom@codethink.co.uk>

# System imports

from collections import Mapping

from collections.abc import Mapping

# BuildStream toplevel imports

from .._exceptions import LoadError, LoadErrorReason

import os

from functools import cmp_to_key

from collections import Mapping, namedtuple

from collections import namedtuple

from collections.abc import Mapping

import tempfile

import shutil