This PR contains some clean-up work following the first phase of porting apache beam to Python 3.
- **Remove six dependency** When starting the porting work, we decided to use the future package instead of the six package, since it allows us to port our code forward instead of back. This should simplify the future addition of Python 3 code and the refactoring if Python 2 support would ever be dropped. - **Run py2to3 pylint on apache_beam module** During porting, the list of modules to run this test on was extended with every ported module. Now that the phase has finished, we can run it on the whole apache_beam module. Post-Commit Tests Status (on master branch) ------------------------------------------------------------------------------------------------ Lang | SDK | Apex | Dataflow | Flink | Gearpump | Samza | Spark --- | --- | --- | --- | --- | --- | --- | --- Go | [](https://builds.apache.org/job/beam_PostCommit_Go_GradleBuild/lastCompletedBuild/) | --- | --- | --- | --- | --- | --- Java | [](https://builds.apache.org/job/beam_PostCommit_Java_GradleBuild/lastCompletedBuild/) | [](https://builds.apache.org/job/beam_PostCommit_Java_ValidatesRunner_Apex_Gradle/lastCompletedBuild/) | [](https://builds.apache.org/job/beam_PostCommit_Java_ValidatesRunner_Dataflow_Gradle/lastCompletedBuild/) | [](https://builds.apache.org/job/beam_PostCommit_Java_ValidatesRunner_Flink_Gradle/lastCompletedBuild/) | [](https://builds.apache.org/job/beam_PostCommit_Java_ValidatesRunner_Gearpump_Gradle/lastCompletedBuild/) | [](https://builds.apache.org/job/beam_PostCommit_Java_ValidatesRunner_Samza_Gradle/lastCompletedBuild/) | [](https://builds.apache.org/job/beam_PostCommit_Java_ValidatesRunner_Spark_Gradle/lastCompletedBuild/) Python | [](https://builds.apache.org/job/beam_PostCommit_Python_Verify/lastCompletedBuild/) | --- | [](https://builds.apache.org/job/beam_PostCommit_Py_VR_Dataflow/lastCompletedBuild/) </br> [](https://builds.apache.org/job/beam_PostCommit_Py_ValCont/lastCompletedBuild/) | --- | --- | --- | --- [ Full content available at: https://github.com/apache/beam/pull/6286 ] This message was relayed via gitbox.apache.org for [email protected]
