title: find a date in a Dataframe column pandas
body: <p>I have column date but I'm not able to find a datetime element in it, even if it exist.
  Please see below.</p>
  <pre><code>x
  datetime.date(2018, 1, 1)
  
  pd.to_datetime(date).dt.date
  0         2018-01-01
  1         2018-01-01
  2         2018-01-01
  3         2018-01-01
  4         2018-01-01
     
  997693    2021-01-08
  997694    2021-01-08
  997695    2021-01-08
  997696    2021-01-08
  997697    2021-01-08
  Name: data, Length: 997698, dtype: object
  
    
  pd.to_datetime(date).dt.date[6]
  datetime.date(2018, 1, 1)
  
  x in pd.to_datetime(date).dt.date
  False
  </code></pre>
  <p>thanks</p>