Версия: falcon-1.4.1-alt1.2

# apt-get install falcon
$ python3 -c "import falcon"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3/site-packages/falcon/__init__.py", line 30, in <module>
    from falcon.api import API  # NOQA
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/site-packages/falcon/api.py", line 21, in <module>
    from falcon import api_helpers as helpers, DEFAULT_MEDIA_TYPE, routing
  File "/usr/lib/python3/site-packages/falcon/api_helpers.py", line 21, in <module>
    from falcon import util
  File "/usr/lib/python3/site-packages/falcon/util/__init__.py", line 29, in <module>
    from falcon.util import structures
  File "/usr/lib/python3/site-packages/falcon/util/structures.py", line 35, in <module>
    class CaseInsensitiveDict(collections.MutableMapping):  # pragma: no cover
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'collections' has no attribute 'MutableMapping'

В сизифе на версии 4.0.2-alt1 не воспроизводится.