How to make subsections of different sizes in a nested pie chart

I am working in python with matplotlib. I am trying to make a nested pie chart where the inner ring is a transportation mode and the outer is the subparts that it consists of.

I have this code:

import matplotlib.pyplot as plt
import numpy as np    

fig, ax = plt.subplots()

size = 0.3
vals = np.array([[60., 32., 13.], [37., 40., 45.], [29., 10., 35.]])

cmap = plt.get_cmap("tab20c")
outer_colors = cmap(np.arange(3)*4)
inner_colors = cmap([1, 2, 3, 5, 6, 7, 9, 10, 11])

ax.pie(vals.sum(axis=1), radius=3-0.9, colors=outer_colors,
       wedgeprops=dict(width=0.9, edgecolor='w'),labels=["Car","Public Transport","Bike"],
       pctdistance=1.1, labeldistance=0.65)

ax.pie(vals.flatten(), radius=3, colors=inner_colors,
       wedgeprops=dict(width=0.9, edgecolor='w'),labels=["Gasoline","Diesel","Electric","Bus","Tram","Train", "Normal Bike","E-Bike","Motorbike"],
       pctdistance=1.1, labeldistance=0.85)

ax.set(aspect="equal", title='')
plt.show()

Which leads to this nested pie chart

I can't figure out how to make the subparts different sizes. For example let's say I wanted to add Tricycle and Unicycle to the Bike category. So Car and Public Transport would be size 3, while Bike is size 5.

I can make all of the subparts be 2, 3 or 4 etc. as long as the lists in the vals array are of the same size. But if I make one of them a different size, then I'll end up with an AxisError. Is there any way to modify this code, so I can freely choose their sizes?

This is about the structure of the data.

Putting everything into a dict gives the user the ability to add whatever they like and the numbers will be consistent.

Here is an example with your data (i have removed the colour map for clarity):

import matplotlib.pyplot as plt


d = {
    "car":{"Gasoline":60,"Diesel":32,"Electric":13},
    "Public Transport":{"Bus":37,"Tram":40,"Train":45}, 
    "bike":{"Normal Bike":29,"E-Bike":10,"Motorbike":35, "Tricycle":5, "Unicycle":15}
    }


# outer values
cars = sum(d['car'].values())
pt = sum(d['Public Transport'].values())
bike = sum(d['bike'].values())

outer_values = [cars, pt, bike]
outer_labels =d.keys()

inner_values = []
inner_labels = []
for vehicle_type in d.values():
    for vehicle_names, vehicle_amounts in vehicle_type.items():
        inner_values.append(vehicle_amounts)
        inner_labels.append(vehicle_names)


fig, ax = plt.subplots()

ax.pie(outer_values, labels=outer_labels, radius=1)
ax.pie(inner_values, labels=inner_labels, radius=0.5)

ax.set_title("My Nested Pie Chart")

plt.show()

And here is the result: