Streamlit's built-in graphing functions

There are three built-in functions for graphing – st.line_chart(), st.bar_chart(), and st.area_chart(). They all work similarly by trying to figure out what variables you're already trying to graph, and then put them into a line, bar, or area chart, respectively. In our dataset, we have a variable called dbh, which is the width of the tree at chest height. First, we can group our DataFrame by dbh, and then push that directly to the line chart, bar chart, and area chart. The following code should group our dataset by width, count the unique trees of each width, and then make a line, bar, and area chart of each:

import streamlit as st
import pandas as pd
st.title('SF Trees')
 st.write('This app analyses trees in San Francisco using'
         ' a dataset kindly provided by SF DPW')
 trees_df = pd.read_csv('trees.csv')
 df_dbh_grouped = pd.DataFrame(trees_df.groupby(...