i try to devellop a custom module 
when i run it . this bug is shown 

 File "c:\program files (x86)\odoo 12.0\server\odoo\addons\base\models\ir_ui_view.py", line 360, in _check_xml
    raise ValidationError(_('Invalid view %s definition in %s') % (view.name, view.arch_fs))
odoo.tools.convert.ParseError: "Invalid view construction.estimation.form definition in estimation/views/estimation.xml
None" while parsing file:/c:/program files (x86)/odoo 12.0/server/odoo/addons/estimation/views/estimation.xml:32, near
<record id="estimation_form" model="ir.ui.view">
            <field name="name">construction.estimation.form</field>
            <field name="model">construction.estimation</field>
            <field name="arch" type="xml">
                <form string="estimations">
                    <header>
                        <button name="action_confirm" type="object" groups="base.user_admin" states="Draft" string="confirm" class="oe_highlight"/>
                        <button name="action_done" type="object" groups="base.user_admin" states="Confirm" string="done" class="oe_highlight"/>
                        <field name="state" widget="statusbar" statusbar_visible="Draft,Confirm,Done"/>
                    </header>
                    <sheet>
                        <div class="oe_button_box" name="button_box">
                            <button name="open_pricing" type="object" class="oe_stat_button" icon="fa-tachometer">
                                <field string="Pricing" widget="statinfo"/>
                            </button>
                        </div>
                        <div class="oe_title">
                            <h1>
                                <field name="name_seq_estimation" readonly="1"/>
                            </h1>
                        </div>
                        <group>
                                <field name="project_id"/>
                        </group>
                        <group>
                            <group name="mould" string="Mould">
                                   <field name="Quantity"/>
                                   <field name="Price"/>
                            </group>
                            <group name="Production" string="Production">
                                   <field name="Row_materials"/>
                                   <field name="Manpower"/>
                                   <field name="Steel_works"/>
                                   <field name="Others"/>
                            </group>
                        </group>
                        <group>
                            <group name="Delivery" string="Delivery">
                               <field name="Delivery"/>
                            </group>
                            <group name="Erection" string="Erection">
                               <field name="Estimated_MM"/>
                               <field name="Estimated_M"/>
                            </group>
                            <group name="Indirect_cost" string="Indirect Costs">
                               <field name="Indirect_cost"/>
                            </group>
                            <group>
                                <field name="File"/>
                            </group>
                        </group>
                        <group>
                            <group name="Summary" string="Summary Percent">
                            <field name="Mould_percent" widget="progressbar"/>
                            <field name="Production_percent" widget="progressbar"/>
                            <field name="Delivery_percent" widget="progressbar"/>
                            <field name="Erection_percent" widget="progressbar"/>
                            <field name="Indirect_cost_percent" widget="progressbar"/>
                        </group>
                        </group>
                        <group>
                            <group name="Summary" string="Price (m²)">
                            <field name="Mould_price" widget="monetary"/>
                            <field name="Production_price" widget="monetary"/>
                            <field name="Delivery_price" widget="monetary"/>
                            <field name="Erection_price" widget="monetary"/>
                            <field name="Indirect_cost_price" widget="monetary"/>
                        </group>
                        <group class="oe_subtotal_footer oe_right" colspan="2" name="sale_total">
                                <field name="Mould" widget="monetary"/>
                                <field name="Production" widget="monetary"/>
                                <field name="Delivery" widget="monetary"/>
                                <field name="Erection" widget="monetary"/>
                                <field name="Indirect_cost" widget="monetary"/>
                                <div class="oe_subtotal_footer_separator oe_inline o_td_label">
                                    <label for="amount_total"/>
                                </div>
                                <field name="amount_total" nolabel="1" class="oe_subtotal_footer_separator" widget="monetary"/>
                        </group>
                        </group>
                    </sheet>
                    <div class="oe_chatter">
                        <field name="message_follower_ids" widget="mail_followers" groups="base.group_user"/>
                        <field name="activity_ids" widget="mail_activity"/>
                        <field name="message_ids" widget="mail_thread"/>
                    </div>
                </form>
            </field>
        </record>