Restructure our python module. A lot.

src/pretix/plugins/timerestriction/models.py

@@ -0,0 +1,24 @@
+from django.db import models
+from django.utils.translation import ugettext_lazy as _
+
+from pretix.base.models import BaseRestriction
+
+
+class TimeRestriction(BaseRestriction):
+    """
+    This restriction makes an item or variation only available
+    within a given time frame. The price of the item can be modified
+    during this time frame.
+    """
+
+    timeframe_from = models.DateTimeField(
+        verbose_name=_("Start of time frame"),
+    )
+    timeframe_to = models.DateTimeField(
+        verbose_name=_("End of time frame"),
+    )
+    price = models.DecimalField(
+        null=True, blank=True,
+        max_digits=7, decimal_places=2,
+        verbose_name=_("Price in time frame"),
+    )