This assert also now breaks the flow

src/lctime/characterization/ngspice_subprocess.py

@@ -119,7 +119,7 @@ def simulate_cell(
         if isinstance(voltage, PieceWiseLinear):
             input_voltages_active[net] = voltage
         else:
-            assert isinstance(voltage, float), "Voltage needs to be a float or a piecewise linear function."
+            #assert isinstance(voltage, float), "Voltage needs to be a float or a piecewise linear function."
             input_voltages_static[net] = voltage
 
     logger.debug("Static input voltages: {}".format(sorted(list(input_voltages_static.keys()))))