'Send the package to the service provider
:param pickings: A recordset of pickings
:return list: A list of dictionaries (one per picking) containing of the form::
{ \'exact_price\': price,
\'tracking_number\': number }'

def send_shipping(self, pickings):

    self.ensure_one()
    if hasattr(self, ('%s_send_shipping' % self.delivery_type)):
        return getattr(self, ('%s_send_shipping' % self.delivery_type))(pickings)
