title: Odoo takes from 1 to 2 positional arguments but 3 were given
body: <p>I am very new in Odoo and Python, I am creating a module, I define one of the modules as:</p>
  
  <pre><code>class Tag(models.Model):
      _name = 'todo.task.tag'
      name = fields.Char('Name', 40)
  </code></pre>
  
  <p>However, when I install the module it shows this error:</p>
  
  <pre><code>File "/mnt/extra-addons/todo_ui/models/models.py", line 65, in Tag
      name = fields.Char('Name', 40)
  TypeError: __init__() takes from 1 to 2 positional arguments but 3 were given
  </code></pre>