A bug need to adjust about ml-in-action-code-and-note

[stonycat]

@wheniseeyou thank you, in python3.6 it may works by changing like this:

def getNumleafs(myTree):
	numLeafs =0#初始化节点数
	#firstSides = list(myTree.keys())
	#firstStr = firstSides[0]
	#secondDict = myTree[firstStr]
         #for key in secondDict.keys():
         for key in myTree.values(): 
               if type(value).__name__=='dict': 
                      numLeafs+=getNumLeafs(value)      
               else:  numLeafs+=1
          return numLeafs 

reference:
https://stackoverflow.com/questions/43729468/decision-tree-str-object-has-no-attribute-keys-python3-6