class GATTCConnection
The GATT Client is the device that requests data from the server, otherwise known as the master device (commonly this might be a phone/tablet/PC). All transactions are initiated by the master, which receives a response from the slave.
connection.disconnect() 
Closes the BLE connection. Returns None.
connection.isconnected() 
Returns True if the connection is still open. False otherwise.
Example:
from network import Bluetooth
import ubinascii
bluetooth = Bluetooth()
# scan until we can connect to any BLE device around
bluetooth.start_scan(-1)
adv = None
while True:
    adv = bluetooth.get_adv()
    if adv:
        try:
            bluetooth.connect(adv.mac)
        except:
            # start scanning again
            bluetooth.start_scan(-1)
            continue
        break
print("Connected to device with addr = {}".format(ubinascii.hexlify(adv.mac)))
connection.services() 
Performs a service search on the connected BLE peripheral (server) a returns a list containing objects of the class 
Example:
# assuming that a BLE connection is already open
services = connection.services()
print(services)
for service in services:
    print(service.uuid())