Fetch the account numbers for a user by their user_id.

Arguments:

def api.users.account_numbers(
  user_id: str = None, # User ID
):

Returns list of dict in the form:

[
  { 
    'account_number': <str>,
    'description': <str>,
    'invoice_email': <str>,
    'valid_from': <None | datetime>,  
    'valid_until': <None | datetime>,  
  },
...
]

Example:

groups = api.users.account_numbers(user_id="foo") # groups = [ <dict> ]