AssertionError: 22 columns passed, passed data had 21 columns
<p>This is my code:</p>

<pre><code>from urllib import urlopen
from bs4 import BeautifulSoup
import pandas as pd

url = "http://www.basketball-reference.com/draft/NBA_2014.html"
html = urlopen(url)
soup = BeautifulSoup(html)
column_headers = [th.getText() for th in soup.findAll('tr',limit=2)[1].findAll('th')]
data_rows = soup.findAll('tr')[2:]
player_data = [[td.getText() for td in data_rows[i].findAll('td')] for i in range(len(data_rows))] #PLAYER DATA 

type(soup)
type(data_rows)

df = pd.DataFrame(player_data,columns=column_headers)
</code></pre>

<p>The error seems to occur in the last line.</p>