Python Basics: Recursive function return value (return) error

The return statement is used to exit the function and return an expression to the caller. return without parameters (or write a return statement),
Default returns NONE. None is a special value, and its data type is nonetype. Nonetype is a special type of Python, and it has only one value of none.
It does not support any operations or any built-in methods, and any other data type comparison is equal to always return false, or none can be assigned to any variable ...

1 when the function does not have an explicit return, the default value of None is returned

2 "When the recursive function has a return, return in the place of recursion, otherwise it will always return none.

1 Import Time2 defBinary_search (data,find_n):3len=len (data)4     ifLen==1:5         ifdata[0]==Find_n:6             #print ("Found, in%d"% (1))7             return18         Else:9             #print ("Not Found")Ten             return0 One     eliflen==2: A         ifdata[0]==Find_n: -             #print ("Found, in%d"% (1)) -             return1 the         elifdata[1]==Find_n: -             #print ("Found, in%d"% (2)) -             return1 -         Else: +             #print ("Not Found") -             return0 +     Else:         AMid_n=int (LEN/2) atMid_val=Data[mid_n] -         ifmid_val==Find_n: -              #print ("Found, in%d"% (mid_n+1)) -              return1 -         elifmid_val<Find_n: -Right_val=Data[mid_n:] in              returnBinary_search (right_val,find_n) -         Else: toLeft_val=Data[:mid_n] +              returnBinary_search (left_val,find_n) -  the defsplit_data (n): *start=0 $stop=1000Panax NotoginsengFlag=1 -len=N the      whileflag: +         iflen>1000: AData=[x forXinchRange (start,stop,1)] the             yieldData +start=start+1000 -stop=stop+1000 $len=len-1000 $         Else: -Data=[x forXinchRange (start,n,1)] -             yieldData theflag=0 -         Wuyi          the if __name__=="__main__": -t0=time.time () Wu      forDatainchSplit_data (10000000000000): -F=binary_search (data,999999999) About         #print (f) $         ifF: -             Print("have been found") -              Break -T1=time.time ()-T0 A     Print(t1)

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Elif Mid_val<find_n:
Right_val=data[mid_n:]
return binary_search (right_val,find_n)

Else
Left_val=data[:mid_n]
return binary_search (left_val,find_n)

Python Basics: Recursive function return value (return) error