Seaborn how do I get this line (condifence bounds) in the line plot?

Question

I have a problem. I would like to display the frequency of the months in a linear progression. In doing so, I group the months and show them linearly. I would like to get this blue thick line. How do I get this thick blue line (condifence bounds)?

d = {
    "customerId": [1, 1, 1, 1, 1, 2, 3, 3],
    "fromDate": [
        "2022-06-01",
        "2022-05-25",
        "2022-05-25",
        "2022-05-20",
        "2021-09-05",
        "2022-06-02",
        "2021-03-01",
        "2021-02-01",
    ],
    "sales": [100, 20, 50, 30, 40, 80, 50, 20],
}
df = pd.DataFrame(data=d)
df["fromDate"] = pd.to_datetime(df["fromDate"], errors="coerce")

df['fromDate_month'] = pd.to_datetime(df['fromDate'], errors='coerce').dt.month
df_month = df['fromDate_month']
plt.figure(figsize=(14,5))
ax = sns.lineplot(x=df_month.value_counts().index, y=df_month.value_counts())

What I have

What I want

Answer 1

Your second plot has upper and lower bounds confidence bounds. Your first chart is what you get with your made dataframe, is the problem style of the plot or you also want the condifence bounds?
If yes then do this before running plot:

import matplotlib.pyplot as plt
%matplotlib inline
plt.style.use('seaborn')