Establish a connection to a TraCI-Server and store it under the given
    label. This method is not thread-safe. It accesses the connection
    pool concurrently.

def init(port=8813, numRetries=10, host="localhost", label="default"):
    """
    Establish a connection to a TraCI-Server and store it under the given
    label. This method is not thread-safe. It accesses the connection
    pool concurrently.
    """
    _connections[label] = connect(port, numRetries, host)
    switch(label)
    return getVersion()