from .base import Shipper


class DHL(Shipper):
    barcode_pattern = r'^\d{10}$'
    shipper = 'DHL'

    @property
    def valid_checksum(self):
        sequence, check_digit = self.tracking_number[:-1], self.tracking_number[-1]
        return int(sequence) % 7 == int(check_digit)

from .base import Shipper


class DHL(Shipper):
    barcode_pattern = r'^\d{10}$'
    shipper = 'DHL'

--- 
+++ 
@@ -4,3 +4,8 @@
 class DHL(Shipper):
     barcode_pattern = r'^\d{10}$'
     shipper = 'DHL'
+
+    @property
+    def valid_checksum(self):
+        sequence, check_digit = self.tracking_number[:-1], self.tracking_number[-1]
+        return int(sequence) % 7 == int(check_digit)
Add DHL waybill checksum validation
