title: TypeError: 'NoneType' object is not subscriptable
body: <p>The error: <code>names = curfetchone()[0]</code></p>
  
  <pre><code>TypeError: 'NoneType' object is not subscriptable. 
  </code></pre>
  
  <p>I tried checking the indentation but still there's an error. I read that maybe the variable names returns 'None' if there is no record of the filename in the database.</p>
  
  <p>I use the same variable 'names' in other 'def' and it works fine. I'm sure it has to do with the 'None' value being returned. </p>
  
  <pre><code>global filename
  global t
  try:
      con = sqlite3.connect('textdb.db')
      cur = con.cursor()
  
      filename = tkinter.simpledialog.askstring("Open file...", "Input filename to open:")
  
      if filename != None:
          cur.execute("SELECT file_name FROM file_info WHERE file_name = ?", (filename,))
          names = cur.fetchone()[0]
          same = str(names)
          if filename == same:
              cur.execute("SELECT file_content FROM file_info WHERE file_name = ?", (filename,))
              content = cur.fetchone()[0]
              t = str(content)
              text.delete(0.0, END)
              text.insert(0.0, t)
          else:
              result = tkinter.messagebox.askyesno(title="File doesn't exist", message="'"+(filename)+"' doesn't exist. Make a new file using '"+(filename)+"'?")
              if result == True:
                  cur.execute("SELECT COUNT(*) FROM file_info")
                  count_row = cur.fetchone()
                  cntdata = count_row[0]
                  incr = (cntdata + 1)
                  t = str(text.get(0.0, END))
                  curtime = str(ctime())
                  cur.execute("INSERT OR IGNORE INTO file_info VALUES(?, ?, ?, ?, ?)", (incr, filename, t, curtime, curtime,))
                  con.commit()
  
  except sqlite3.Error:
      if con:
          con.rollback()
  finally:
      if con:
          con.close()
  </code></pre>