diff --git a/hardware_components/mux_2024_rev_0_0.py b/hardware_components/mux_2024_rev_0_0.py
index c7d927445a2dc73810bae5e29c5a8a5e34823618..ed2674f600ca04165b40335188aa2cbe49f8d653 100644
--- a/hardware_components/mux_2024_rev_0_0.py
+++ b/hardware_components/mux_2024_rev_0_0.py
@@ -96,7 +96,7 @@ class Mux(MuxAbstract):
         else:
             self._tca = adafruit_tca9548a.TCA9548A(self.controller.bus, tca_address)[tca_channel]
         self._mcp_addresses = (kwargs.pop('mcp_0', '0x22'), kwargs.pop('mcp_1', '0x23'))  # TODO add assert on valid addresses..
-        self._mcp = (None, None)
+        self._mcp = [None, None]
         self.reset()
         if self.addresses is None:
             self._get_addresses()