I am new to modules development. I want to add attributes and features to the existing crm_lead object. Working on 8.0 version.

I have created a new module with the scaffold feature. In the `__openerp__.py` manifest, I have added a dependency

    # any module necessary for this one to work correctly

    'depends': ['base','CRM'],

When trying to import the module, I get the error

 raise orm.except_orm(_('Error'), _("You try to install module '%s' that depends on module '%s'.\nBut the latter module is not available in your system.") % (module.name, dep.name,)) 
except_orm: (u'Error', u"You try to install module 'yvleads' that depends on module 'CRM'.\nBut the latter module is not available in your system.")

Here is the skeletton of the class. I have tried various import (from openerp, from CRM, import crm, import crm_lead) without much success.

class yvleads(models.Model):

    _inherit = 'crm.crm_lead'

    _name = 'yvleads.yvleads'

    name = fields.Char()

    _column = { 'Last_Action': fields.Char('Last_Action', size=240, required=False) }

Any hint here or link to a good practise document or code example to override or add info to existing standard modules?

Thanks