python - attribute error: when trying to write in form xml -

i trying update form view xml. here code:

def update_column(self,cr,uid,ids,context=none):         id in ids:             temp=self.pool.get('deg.form').browse(cr,uid,id)             fields={'myname':temp.name,'mytype':temp.data_type}              self._columns.update(fields)             print (self._columns)         result = super(deg_form, self).create(cr,uid,{},context=none)             return result   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, 145)         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': '"+objn.name+"', 'store': true,'size': 128}}"        res['fields']=eval(str_fields)               temp_arch="""<field name="father_name" />"""              fields_string=res['arch']        index_of_end_group=fields_string.find('</group>')        fields_string=fields_string[:index_of_end_group] + " " +temp_arch + " "+fields_string[index_of_end_group(inlove)               res['arch']=fields_string         return res 

but getting error

attributeerror: 'unicode' object has no attribute '_type' 

here stacktrace:

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     result = super(deg_form, self).create(cr,uid,{},context=none)   file "/home/arsalan/openerp-7.0/openerp/osv/orm.py", line 4372, in create     bool_fields = [x x in self._columns.keys() if self._columns[x]._type=='boolean'] attributeerror: 'unicode' object has no attribute '_type' 

i trying since 2 days , out of ideas. or guide solution highly appreciated. thanks

one of self._columns unicode object. reason update self._columns wrong type of data. keeps {'field_name':openerp.osv.fields.date object} here:

temp=self.pool.get('deg.form').browse(cr,uid,id) fields={'myname':temp.name,'mytype':temp.data_type} self._columns.update(fields) 

you update _columns weird values.