I created a form to get data for a store voucher. But on clicking the "save" button, it gives me this error:

except_osv: (u'ValidateError', u'The value "in" for the field "product_template.type" is not in the selection')

I don't know where to look. Please can someone help me with this. Any help will be appreciated Thank you

My view code:

<record id="store_issuing_voucher_form" model="ir.ui.view">
        <field name="name">store.issuing.voucher.form</field>
        <field name="model">store.issuing.voucher</field>
        <field name="arch" type="xml">
            <form string="Store Issuing Voucher" version="7.0"><sheet string="Store Issuing Voucher">


                        <group string="Requestor Details" col="4">
                            <field name="employee_id" on_change="onchange_employee_id(employee_id,department_id)" />
                            <field name="department_id"/>
                            <field name="date" />
                            <field name="organizational_id"  />
                            <field name="fund_code"  />
                            <field name="program_code"  />
                            <field name="location_code"  />
                            <field name="manager_id" />                                 
                        </group>
                    <group string="Product Item Details">

                        <notebook>
                    <page string="Store Products Lines">
                        <field name= "mystore_product_ids" />
                        <field name="note" placeholder="Add any note..." class="oe_inline" />
                    </page>

                        </notebook> 
                    </group>                        
                </sheet>
                <div class="oe_chatter">
                    <field name="message_follower_ids" widget="mail_followers"/>
                    <field name="message_ids" widget="mail_thread"/>
                </div>
            </form>
        </field>
    </record>
    <!-- End of Store Issuing Voucher Form View -->

     <!-- Store Issuing Voucher tree View -->


    <record id="store_issuing_voucher_tree" model="ir.ui.view">
        <field name="name">store.issuing.voucher.tree</field>
        <field name="model">store.issuing.voucher</field>
        <field name="type">tree</field>
        <field name="arch" type="xml">
            <tree string="Vouchers" >

                <field name="product_id"/> 
                <field name="employee_id"/>
                <field name="department_id" />
                <field name="organizational_id"/>
                <field name="program_code"/>
                <field name="value"/>
                <field name="date"/>

            </tree>
        </field>
    </record>

    <record id="store_issuing_voucher_form" model="ir.ui.view">
        <field name="name">store.issuing.voucher.form</field>
        <field name="model">store.issuing.voucher</field>
        <field name="arch" type="xml">
            <form string="Store Issuing Voucher" version="7.0">
                <sheet string="Store Issuing Voucher">
                    <group string="Requestor Details" col="4">
                        <field name="employee_id" on_change="onchange_employee_id(employee_id,department_id)" />
                        <field name="department_id"/>
                        <field name="date" />
                        <field name="organizational_id" />
                   </group>
                </sheet>
            </form>
        </field>
</record>