The following Code is :---

class prakrutiTemplate(models.Model):

 _inherit = 'product.template'

pm_name = fields.One2many('packing.material.line','name',string= 'PName', store=True)

ps_name = fields.One2many('product.specification.line','name',string= 'PSName', store=True)

def _get_product_template_type(self, cr, uid, context=None):

res = super(prakrutiTemplate, self)._get_product_template_type(cr, uid, context=context)

if 'packing' not in [item[0] for item in res]:

res.append(('packing', _('Packing Materials')))

return res

class packingMaterialline(models.Model):

_name= 'packing.material.line'

name = fields.Many2one('packing.material.line', string= 'Package name')

pname = fields.Many2one('packing.material',string='Name')

desc = fields.Char(related='pname.desc',string='Package Description')

class productSpecificationline(models.Model):

_name = 'product.specification.line'

name = fields.Many2one('product.specification.line',string= 'Name')

pname = fields.Many2one('product.specification', string= 'Name')

parameter = fields.Char(related='pname.desc',string='Product Specification')

class packingMaterial(models.Model):

_name= 'packing.material'

name = fields.Char(string= 'Package name')

desc = fields.Char('Package Description')

class productSpecification(models.Model):

_name= 'product.specification'

name = fields.Char(string= 'Product name')

desc = fields.Char('Specification')