General informations:

• OS name: Debian GNU/Linux
• OS version: sid
• OS architecture: 64 bits
• Result of the command python --version: Python 3.5.1+

For GNU/Linux users:

• Display server protocol and version, if known: X server
• Desktop Environment: XFCE 4
• Composite Window Manager name and version: Cairo v1.14.6

A description of the issue with optional steps to reproduce.

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