Hi all, i am stuck in weird problem. i am trying to open my form view in button click event using

res = super(deg_form,self).fields_view_get(cr, uid, view_id=None, view_type='form', context=None, toolbar=False, submenu=False)

but on clicking button i get

Server Traceback (most recent call last):
  File "/home/arsalan/openerp-7.0/openerp/addons/web/session.py", line 90, in send
    return openerp.netsvc.dispatch_rpc(service_name, method, args)
  File "/home/arsalan/openerp-7.0/openerp/netsvc.py", line 295, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/home/arsalan/openerp-7.0/openerp/service/web_services.py", line 614, in dispatch
    res = fn(db, uid, *params)
  File "/home/arsalan/openerp-7.0/openerp/osv/osv.py", line 188, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File "/home/arsalan/openerp-7.0/openerp/osv/osv.py", line 131, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/home/arsalan/openerp-7.0/openerp/osv/osv.py", line 198, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/home/arsalan/openerp-7.0/openerp/osv/osv.py", line 185, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/home/arsalan/openerp-7.0/openerp/addons/system/myform.py", line 131, in update_column
    res = super(deg_form,self).fields_view_get(cr, uid, view_id=None, view_type='form', context=None, toolbar=False, submenu=False)
  File "/home/arsalan/openerp-7.0/openerp/osv/orm.py", line 2260, in fields_view_get
    xarch, xfields = self.__view_look_dom_arch(cr, user, result['arch'], view_id, context=ctx)
  File "/home/arsalan/openerp-7.0/openerp/osv/orm.py", line 1912, in __view_look_dom_arch
    fields = self.fields_get(cr, user, None, context)
  File "/home/arsalan/openerp-7.0/openerp/osv/orm.py", line 3511, in fields_get
    (field.groups and not self.user_has_groups(cr, user, groups=field.groups, context=context)):
AttributeError: 'unicode' object has no attribute 'groups'

Plz let me know what i am doing wrong here.

Thanks

Edit

def fields_view_get(self, cr, uid, view_id=None, view_type='form', context=None, toolbar=False, submenu=False): 
       res = super(deg_form,self).fields_view_get(cr, uid, view_id, view_type, context, toolbar, submenu) 
       objn = self.pool.get('deg.form').browse(cr, uid, id) 
       if view_type=='form':
              str_fields=str(res['fields']) 
              str_fields=str_fields[:len(str_fields)-1]+ ", 'father_name' :{'selectable': True, 'views': {},'type':'char', 'string': 'father Name', 'store': True,'size': 128}}"
               res['fields']=eval(str_fields)
               temp_arch="""<field name="father">"""