title: How to apply get_group to groupby data in pandas when the groupby column is a category
body: <pre><code>age_cleaned_titanic_df.groupby('Age_group').mean()
  age_cleaned_titanic_df.groupby('Age_group').get_group((0,10])
  </code></pre>
  
  <p>The get_group function gives me errors as the 'Age_group' column has values which are half-open indices of bins. 
  (0,10]
  (10,20]
  ...
  ...
  (70,80]. </p>
  
  <p>How do I then perform the get_group() method? Most of the examples in the documentation and stackoverflow talk about columns values which are strings/numbers where get_group() becomes straightforward. How to do it when the groupby column is a category? </p>