Matplotlib+Jupyter stops rendering animation when run inside a function

After getting a matplotlib animation to run successfully inside a Vscode Juypter notebook cell, I decided to refactor the matplotlib animation code into a function but this causes the matplotlib figure to stop showing and display a warning

UserWarning: Animation was deleted without rendering anything. This is most likely not intended. To prevent deletion, assign the Animation to a variable, e.g. anim, that exists until you output the Animation using plt.show() or anim.save().

Initial working code:

import matplotlib.pyplot as plt
import matplotlib.animation
import numpy as np

plt.rcParams["animation.html"] = "jshtml"
plt.rcParams["figure.dpi"] = 100
plt.ioff()

def animate(frame_num):
    x = np.linspace(0, 2*np.pi, 100)
    y = np.sin(x + 2*np.pi * frame_num/100)
    line.set_data((x, y))
    return line

fig, ax = plt.subplots()
line, = ax.plot([])
ax.set_xlim(0, 2*np.pi)
ax.set_ylim(-1.1, 1.1)

matplotlib.animation.FuncAnimation(
    fig, animate, frames=10, blit=True
)

Non-working refactored code:

import matplotlib.pyplot as plt
import matplotlib.animation
import numpy as np

plt.rcParams["animation.html"] = "jshtml"
plt.rcParams["figure.dpi"] = 100
plt.ioff()

def animate(frame_num):
    x = np.linspace(0, 2*np.pi, 100)
    y = np.sin(x + 2*np.pi * frame_num/100)
    line.set_data((x, y))
    return line
    
def generate_animation():
    fig, ax = plt.subplots()
    line, = ax.plot([])
    ax.set_xlim(0, 2*np.pi)
    ax.set_ylim(-1.1, 1.1)

    anim = matplotlib.animation.FuncAnimation(
        fig, animate, frames=10, blit=True
    )
    
    plt.show()

    return anim

anim = generate_animation()

Also tried adding %matplotlib notebook or %matplotlib widget to the start of the Jupyter notebook cell, but the same error occurs.

Is there a way to get the matplotlib.animation.FuncAnimation working when its running from inside a function?