How to add a title to a barplot in Python

import matplotlib.pyplot as plt
import pandas as pd

# We generate a dataframe with some random data
df = pd.DataFrame(index = ['2018', '2019', '2020', '2021'], 
                  data={"sales": [28429, 41771, 55238, 120681]})

# We set our canvas
fig, axes = plt.subplots(1,1, figsize=(8,6))

# We do a bar plot on the axes
axes.bar(x=df.index,
         height=df["sales"], 
         label="Sales in USD")

# We set a title
axes.set_title("Sales per year")

# Change the labels
axes.set_xlabel("Year")
axes.set_ylabel("In USD")

# Add the legend
axes.legend(loc='upper left')

# Fixing the layout to fit the size
fig.tight_layout()

# Showing the plot
plt.show()

import matplotlib.pyplot as plt
import pandas as pd

# We generate a dataframe with some random data
df = pd.DataFrame(index = ['2018', '2019', '2020', '2021'], 
                  data={"sales": [28429, 41771, 55238, 120681]})

# We plot the data as bar chart.
df.plot(kind="bar", title="Sales per year")