title: Pythonic type hints with pandas?
body: <p>Let's take a simple function that takes a str and returns a dataframe:</p>
  
  <pre><code>import pandas as pd
  def csv_to_df(path):
      return pd.read_csv(path, skiprows=1, sep='\t', comment='#')
  </code></pre>
  
  <p><strong><em>What is the recommended pythonic way of adding type hints to this function?</em></strong></p>
  
  <p>If I ask python for the type of a DataFrame it returns <code>pandas.core.frame.DataFrame</code>.
  The following won't work though, as it'll tell me that pandas is not defined.</p>
  
  <pre><code> def csv_to_df(path: str) -&gt; pandas.core.frame.DataFrame:
       return pd.read_csv(path, skiprows=1, sep='\t', comment='#')
  </code></pre>