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 and specify your project configuration file:

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

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

env: <odoo.api.Environment object at 0x10e3277f0>
odoo: <module 'odoo' from '/home/parth/community/odoo/__init__.py'>
openerp: <module 'odoo' from '/home/parth/community/odoo/__init__.py'>
self: res.users(1,)
Python 3.6.5 (default, Apr 25 2018, 14:23:58) 
[GCC 9.3.0] 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.