title: TypeError: coercing to Unicode: need string or buffer, NoneType found
body: <p>I am trying to create a SQL string from a python script.</p>
  
  <p>this is the code:</p>
  
  <pre><code>sql_query = ('insert into ithelpdesk ' 
          '(id,display_id,subject,description,priority,status,requester_name,source,responder_id,due_by,updated_at,frDueBy,ticket_type,created_at)'
          ' values ('
          '"' + str(data['id']) + '",'
          '"' + str(data['display_id']) + '",'
          '"' + data['subject'] + '",'
          '"' + data['description'] + '",'
          '"' + str(data['priority']) + '",'
          '"' + str(data['status']) + '",'
          '"' + data['requester_name'] + '",'
          '"' + str(data['source']) + '",'
          '"' + str(data['responder_id']) + '",'
          '"' + str(data['due_by']) + '",'
          '"' + str(data['updated_at']) + '",'
          '"' + str(data['frDueBy']) + '",'
          '"' + data['ticket_type'] + '",'
          '"' + str(data['created_at']) + '"'
          ')')
  </code></pre>
  
  <p>when I run I am getting this traceback message:</p>
  
  <pre><code>Traceback (most recent call last):
   File "c:\users\swatson\dropbox\source files\winpython\dash\newTickets.py", line 198, in &lt;module&gt;
  main()
   File "c:\users\swatson\dropbox\source files\winpython\dash\newTickets.py", line 159, in main
  addNew(n)
  File "c:\users\swatson\dropbox\source files\winpython\dash\newTickets.py", line 65, in addNew
  '"' + str(data['created_at']) + '"'
  TypeError: coercing to Unicode: need string or buffer, NoneType found
  </code></pre>
  
  <p>Now I know for a fact (by doing a printstr(data['created_at'])) that there is a value at data['created_at'], and I also know that is is the same value as with data['updated_at'] so I am at a loss as to how to resolve this?</p>