Plotting Treasury Yield Curve, how to overlay two yield curves using matplotlib

Question

I am trying to create a graph of the treasury yield curve to compare the rates from two separate dates. I am having difficulty with combining the two curves and creating a clean graph. My question: how do I plot the two yield curves together, with the yields (rates) are on the y-axis, and the maturities (2yr, 5yr, 10yr, 20yr, 30yr) are on the x-axis?

import numpy as np
import pandas as pd
import datetime as dt
import pandas.io.data as web
import matplotlib.pyplot as plt
import quandl as q
from pandas import DataFrame
import matplotlib
matplotlib.style.use('ggplot')

treasury = q.get("USTREASURY/YIELD", trim_start="2000-01-01", returns="pandas")

fig, ax = plt.subplots()

treas = DataFrame(treasury)
treas.drop(treas.columns[[0,1,2,3,5,7]], axis=1, inplace=True)
today = treas.iloc[-1:]
first = treas.iloc[:1]
first = first.T
today = today.T

ax.plot(first, 'o')
ax.plot(today, 'x')

#first.plot(marker='o')
#today.plot(marker='o')
plt.show()

Answer 1

FYI: I'm using python 3.8 and spyder with anaconda. I spent a lot of time troubleshooting the 'module not found error for Quandl only to discover it should be quandl (lowercase).