Fixed collection of classes with custom __new__ method. Fixes #1579.

[Stranger6667]

Thanks for submitting a PR, your contribution is really appreciated!

Here's a quick checklist that should be present in PRs:

• Target: for bug or doc fixes, target master; for new features, target features;
• Make sure to include one or more tests for your change;
• Add yourself to AUTHORS;
• Add a new entry to CHANGELOG.rst
  • Choose any open position to avoid merge conflicts with other PRs.
  • Add a link to the issue you are fixing (if any) using RST syntax.
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[coveralls]

Coverage increased (+0.004%) to 92.294% when pulling c1bcf19 on Stranger6667:issue1579-invalid-class into 018acc6 on pytest-dev:master.

[nicoddemus]

Thanks! Looks good!

Could you please rebase it into the latest master? Unfortunately the CHANGELOG must have conflicted now that I merged another PR. 😞

[The-Compiler]

Please drop the parens there 😉

[Stranger6667]

Done!

[coveralls]

Coverage increased (+0.004%) to 92.294% when pulling de10ccc on Stranger6667:issue1579-invalid-class into 655df7f on pytest-dev:master.

[Stranger6667]

Rebased, now everything should be OK!
@nicoddemus

[coveralls]

Coverage increased (+0.004%) to 92.296% when pulling f7ad173 on Stranger6667:issue1579-invalid-class into d37af20 on pytest-dev:master.

[The-Compiler]

Thanks! Definitely something I did run into in the past as well.

[tomviner]

This is great @Stranger6667, thanks for coming to the sprint!

[Stranger6667]

@tomviner
Thank you for the help on the sprint :)