initial commit

app/apps/transactions/validators.py

@@ -0,0 +1,18 @@
+from django.core.exceptions import ValidationError
+from django.utils.translation import gettext_lazy as _
+
+
+def validate_decimal_places(value):
+    if abs(value.as_tuple().exponent) > 18:
+        raise ValidationError(
+            _("%(value)s has too many decimal places. Maximum is 18."),
+            params={"value": value},
+        )
+
+
+def validate_non_negative(value):
+    if value < 0:
+        raise ValidationError(
+            _("%(value)s is not a non-negative number"),
+            params={"value": value},
+        )