title: Assign constant value to variable python called a server function firestore.SERVER.TIMESTAMP
body: <p>I am trying to assign the same timestamp to a few fields in Firestore. I am using python 3.7</p>
  
  <p>My code to generate the timestamp is this.</p>
  
  <pre><code>current_system_timestamp    = firestore.SERVER_TIMESTAMP
  </code></pre>
  
  <p>I am using the current_system_timestamp to update fields in Firestore. Like this.</p>
  
  <pre><code>   channel_id_doc_ref.set({
                      'timestamp'  : current_system_timestamp,
                      'initiator_name'       : user_name
                  })
  
   notes_doc_ref.set({
              'note'         : chat_note
              'timestamp_entered'     : current_system_timestamp
          })
  </code></pre>
  
  <p>Unfortunately the two timestamp values after they are set in Firestore is different - by miliseconds. This leads me to believe that I need to declare current_system_timestamp as a constant in python. How do I do this? </p>