'Return request that would result from clicking on a control.
The request object is a urllib2.Request instance, which you can pass to
urllib2.urlopen (or ClientCookie.urlopen).
Only some control types (INPUT/SUBMIT & BUTTON/SUBMIT buttons and
IMAGEs) can be clicked.
Will click on the first clickable control, subject to the name, type
and nr arguments (as for find_control).  If no name, type, id or number
is specified and there are no clickable controls, a request will be
returned for the form in its current, un-clicked, state.
IndexError is raised if any of name, type, id or nr is specified but no
matching control is found.  ValueError is raised if the HTMLForm has an
enctype attribute that is not recognised.
You can optionally specify a coordinate to click at, which only makes a
difference if you clicked on an image.'

def click(self, name=None, type=None, id=None, nr=0, coord=(1, 1), request_class=urllib2.Request, label=None):

    return self._click(name, type, id, label, nr, coord, 'request', self._request_class)
