'Add a new node to our canvas.'

def addNode(self, node, nodeNum, x, y, name=None):

    if ('Switch' == node):
        self.switchCount += 1
    if ('Host' == node):
        self.hostCount += 1
    if ('Controller' == node):
        self.controllerCount += 1
    if (name is None):
        name = (self.nodePrefixes[node] + nodeNum)
    self.addNamedNode(node, name, x, y)
