remove old definition

InvenTree/plugin/base/integration/mixins.py

@@ -369,42 +369,6 @@ class AppMixin:
         return True
 
 
-class LabelPrintingMixin:
-    """
-    Mixin which enables direct printing of stock labels.
-
-    Each plugin must provide a NAME attribute, which is used to uniquely identify the printer.
-
-    The plugin must also implement the print_label() function
-    """
-
-    class MixinMeta:
-        """
-        Meta options for this mixin
-        """
-        MIXIN_NAME = 'Label printing'
-
-    def __init__(self):  # pragma: no cover
-        super().__init__()
-        self.add_mixin('labels', True, __class__)
-
-    def print_label(self, label, **kwargs):
-        """
-        Callback to print a single label
-
-        Arguments:
-            label: A black-and-white pillow Image object
-
-        kwargs:
-            length: The length of the label (in mm)
-            width: The width of the label (in mm)
-
-        """
-
-        # Unimplemented (to be implemented by the particular plugin class)
-        ...  # pragma: no cover
-
-
 class APICallMixin:
     """
     Mixin that enables easier API calls for a plugin