def get_floating_ip(body_response_server_details, network_name):
    """
    Retrieve the first floating IP from the given network attached to VM
    :param body_response_server_details: (dic) Parsed response. Server details data
    :param network_name (String): Name of the network where floating IP is allocated.
    :return: (String) The floating IP. None if floating IP not found in the given network (VM)
    """
    floating_ip = None
    addresses = body_response_server_details['server']['addresses']
    for address in addresses:
        if address == network_name:
            for net in addresses[address]:
                if net['OS-EXT-IPS:type'] == "floating":
                    floating_ip = net['addr']
                    break

    return floating_ip