I've been trying to animate a series of plots using `matplotlib.animation` to no avail. My data are currently stored in a Pandas dataframe and I want to iterate through a category (in this case, colors) and plot the data corresponding to each color as the following:

```
import pandas as pd
import seaborn as sns
import matplotlib.animation as animation

def update_2(i):
    plt.clf()
    fil_test = test[test['color'] == iterations[i]]
    sns.scatterplot(x = 'size',y = 'score',hue = 'shape',ci = None,
                              palette = 'Set1',data = fil_test)
    ax.set_title(r"Score vs. Size: {} Shapes".format(
        iterations[i]),fontsize = 20)
    ax.legend(loc='center left', bbox_to_anchor=(1, 0.5),prop={'size': 12})

test = pd.DataFrame({'color':["red", "blue", "red", 
"yellow",'red','blue','yellow','yellow','red'], 
        'shape': ["sphere", "sphere", "sphere", 
"cube",'cube','cube','cube','sphere','cube'], 
        'score':[1,7,3,8,5,8,6,2,9],
        'size':[2,8,4,7,9,8,3,2,1]})
iterations = test['color'].unique()
i = 0
fig2 = plt.figure(figsize = (8,8))
ax = plt.gca()
plt.axis()
ax.set_xlabel("size",fontsize = 16)
ax.set_ylabel("score",fontsize = 16)
ax.set_xlim(0,10)
ax.set_xlim(0,10)
ax.set_xticks(np.linspace(0,10,6))
ax.set_yticks(np.linspace(0,10,6))
ax.tick_params(axis='both', which='major', labelsize=15)

ani = animation.FuncAnimation(fig2,update_2,frames = len(iterations))
ani.save("test.mp4", dpi=200, fps=1)

```

However, 4 issues arise from this code:

1. Even though I saved my animation to the `ani` variable, it doesn't seem to display the data associated with each different color.
2. The title doesn't show up/update appropriately for each color.
3. Calling on `ax.legend` produces the following error/Warning: `No handles with labels found to put in legend.`
4. Trying to save the animation produces the following Error: `MovieWriterRegistry' object is not an iterator`

Could someone explain why these issues currently pop up and is there a better way to write/format my code for animated plots?