title: Pandas Pivot Error "Exception: Data must be 1-dimensional"
body: <p>I am using Pycharm (version 2018.2.4) with Python 3.6.7 running on it.</p>
  
  <p>I currently try to use the pandas pivot function, but even the sample code:</p>
  
  <pre><code>import pandas as pd
  df = pd.DataFrame({'foo':['one', 'one', 'one', 'two', 'two','two'],'bar': 
    ['A', 'B', 'C', 'A', 'B', 'C'],'baz': [1, 2, 3, 4, 5, 6],'zoo': ['x', 
     'y', 'z', 'q', 'w', 't']})
  df.pivot(index='foo', columns='bar', values=['baz', 'zoo'])
  </code></pre>
  
  <p>leads to the error:
  <em>Exception: Data must be 1-dimensional</em></p>
  
  <p>This is only the case when I pass a list of columns to the values parameter, however this example is taken straight from the function help:
  <a href="https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.pivot.html" rel="nofollow noreferrer">https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.pivot.html</a></p>
  
  <p>It used to work for me in the past and has stopped working this week, not sure why. My pandas version is 0.23.4 and numpy version is 1.15.4.</p>
  
  <p>Does anybody know what is causing this/how to fix it?</p>
  
  <p>Thanks!</p>