Before starting, make sure you've installed the dependencies;
pip install pandas cvxpy matplotlib jupyterlab
If you prefer to use the same dataset to follow along you can download it directly or you can fetch it via;
wget https://calmcode.io/datasets/stocks.csv
Given all these preparations, you can use the following code to make the same visual;
import cvxpy as cp
import pandas as pd
df_stocks = pd.read_csv("stocks.csv").iloc[500:1800]
df_stocks.set_index('Date').plot(figsize=(12, 4));
To make the first order differences you need to run;
df_returns = df_stocks.set_index('Date').diff()
df_returns.mean()
df_returns.std()