[Tutor] passing variables to functions

[steve10brink1 at comcast.net]

Hi,

I always assumed that variables could only be passed to functions via function calls unless they are designated as global.  So I was suprised that this code works without any errors.  How does the variable 'b' get indirectly assigned in the function testVar(a)?  I expected an error.  I am using python3 version 3.5.3.

Code:
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def testVar(a):
print(b,a)    #b is from main and not passed thru function call, expect error
return a

print("Test variables in function.....")
b = 23.4
c = testVar(b)
print("Final: ",c)

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Output:

Test variables in function.....
23.4 23.4
Final: 23.4