title: Does uproot4 not support tree.pandas.df(）function anymore?
body: <p>I used to retrieve pandas dataframe from ROOT file using tree.pandas.df() function in Uproot4(2 years ago). However, I got the below errors when I ran my code recently. Could anyone tell me what the problem is?</p>
  <pre><code>f = uproot.open(inputFile)
  treeName = &quot;myTreeName&quot;
  tree = f[treeName]
  myDf = tree.pandas.df('branchName',entrystop=nEvent, flatten = False)
  </code></pre>
  <p>AttributeError: 'Model_TTree_v19' object has no attribute 'pandas'</p>