In order to call the export_stock_level() method from the Odoo shell, you need to perform the following steps:

1. Start the Odoo shell specifying your project configuration file:

    $ ./odoo-bin shell -c project.conf --log-level=error  

2. Check for error messages, and read the information text displayed before the usual Python command-line prompt:

env: <odoo.api.Environment object at 0x7fac2ac2d990>
odoo: <module 'odoo' from '/home/cookbook/odoo/odoo/__init__.pyc'>
openerp: <module 'odoo' from '/home/cookbook/odoo/odoo/__init__.pyc'>
self: res.users(1,)
Python 3.5.2 (default, Sep 14 2017, 22:51:06) 
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

3. Get a recordset for product.product:

    >>> product = env['product.product']  

4. Get the main stock location record:

    >>> location_stock = env.ref('stock.stock_location_stock')

5. Call the export_stock_level() method:

    >>> product.export_stock_level(location_stock)

6. Commit the transaction before exiting:

    >>> env.cr.commit()

7. Exit the shell by pressing Ctrl + D