If you are trying to automate the creation of the task, why even have the module. You can directly create an automated action something on these line (this hasn't been tested and only an outline to illustrate)

Settings > Technical > Automated actions

Hi,

def action_generate_task(self):

for rec in self:

stage = self.env['crm'lead'].search([('stage_id', '=', //add your required stage value],limit=1)

values = {

'name': rec.name',

'user_ids' : rec.user_id.ids,

}

self.env['project.task'].sudo().create(values)

xml:

<record id="action_task_generation" model="ir.cron">
    <field name="name">Auto Task Generation</field>
    <field name="model_id" ref="model_crm_lead"/>
    <field name="state">code</field>
    <field name="code">model.action_generate_task()</field>
    <field name="interval_number">1</field>
    <field name="interval_type">days</field>
    <field name="numbercall">-1</field>
    <field name="active" eval="True"/>
    <field name="doall" eval="True"/>
</record>

Hope it helps