Bug#896394: python-tf2-sensor-msgs: tf2_sensor_msgs fails to import

[Helmut Grohne]

Package: python-tf2-sensor-msgs
Version: 0.5.16-2
Severity: serious
User: helmutg at debian.org
Usertags: python-import

After installing python-tf2-sensor-msgs importing the module tf2_sensor_msgs
into a python interpreter fails with the following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python2.7/dist-packages/tf2_sensor_msgs/__init__.py", line 1, in <module>
    from tf2_sensor_msgs import *
  File "/usr/lib/python2.7/dist-packages/tf2_sensor_msgs/tf2_sensor_msgs.py", line 29, in <module>
    from sensor_msgs.point_cloud2 import read_points, create_cloud
  File "/usr/lib/python2.7/dist-packages/sensor_msgs/point_cloud2.py", line 47, in <module>
    import roslib.message
ImportError: No module named roslib.message

The vast majority of import failures is attributed to missing dependencies.
Often times that manifests as an ImportError or ModuleNotFoundError.
Typically, dependencies should be inserted by dh-python via ${python:Depends}
or ${python3:Depends}. Thus a missing dependency can be caused by incomplete
install_requires in setup.py. Sometimes a missing dependency of a dependency
is the cause, in such cases this bug should be reassigned.

Helmut