Hi, I need to make hide some elements on a button click. How can i do that? currently i tried using 2 functional fields and a character field which doesn't seem to work. here is the xml snippet of what i'm trying to hide.

<sheet attrs="{'invisible':[('historical_concept','=','True')]}">.......</sheet>

and here's the python code

def _historical_concept(self,cr,uid,ids,field_name,argus,context):
    ret_val={}
    for record in self.browse(cr,uid,ids,context):
        if (record.historical_state is not False and record.historical_state == 'concept') or record.state in ['concept']:
            self.write(cr,uid,ids,{'historical_state':None})
            ret_val[record.id]=False
        else:
            ret_val[record.id]=True
    return ret_val

def historical_stage_concept(self,cr,uid,ids,context=None):
    return self.write(cr,uid,ids,{'historical_state':'concept'})

EDIT 1: Button code

<button name="historical_stage_concept" type="object"/>

EDIT 2: _coloumns and _defaults _column is too long so i paste only the relevant part if more is needed please ask.

_columns = {
             'state':fields.selection([
                                     ('concept', 'Concept'),
                                     ('develop', 'Develop'),
                                     ('market', 'Market'),
                                     ('refuse','Rejected')],
                                    'Stage', readonly=True), 
            'historical_state':fields.char(),
            'historical_concept':fields.function(_historical_concept, type='boolean', method=True, string='Historical Concept'),
            'historical_develop':fields.function(_historical_develop, type='boolean', method=True, string='Historical Develop'),
            }

_defaults = {
           'historical_state':None
           }