<field name="base"/>
<field name="base_pricelist_id" attrs="{'invisible':[('base', '!=', -1)],'required': [('base','=', -1)], 'readonly': [('base','!=', -1)]}"/>
</group>
<field name="base"/>
<field name="base_pricelist_id" attrs="{'invisible':[('base', '!=', -1)],'required': [('base','=', -1)], 'readonly': [('base','!=', -1)]}"/>
</group>