title: Pandas DataFrame drop tuple or list of columns
body: <p>When using the <code>drop</code> method for a <code>pandas.DataFrame</code> it accepts lists of column names, but not tuples, despite the <a href="https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.drop.html" rel="nofollow noreferrer">documentation</a>  saying that "<em>list-like</em>" arguments are acceptable. Am I reading the documentation incorrectly, as I would expect my MWE to work.</p>
  
  <p><strong>MWE</strong></p>
  
  <pre><code>import pandas as pd
  df = pd.DataFrame({k: range(5) for k in list('abcd')})
  df.drop(['a', 'c'], axis=1) # Works
  df.drop(('a', 'c'), axis=1) # Errors
  </code></pre>
  
  <p><strong>Versions</strong> - Using Python 2.7.12, Pandas 0.20.3.</p>