async def METHOD_NAME(self):
    """
    Set up initial subscriptions and populate the GUI with data from the
    ledger on startup. Requires that self.client be connected first.
    """
    # Set up a subscriptions for new ledgers
    response = await self.client.request(xrpl.models.requests.Subscribe(
        streams=["ledger"]
    ))
    # The immediate response contains details for the last validated ledger.
    # We can use this to fill in that area of the GUI without waiting for a
    # new ledger to close.
    wx.CallAfter(self.gui.update_ledger, response.result)