[Python] `map` causing infinite loop in Python 3

I have the following code:

def my_zip(*iterables):
iterators = tuple(map(iter, iterables))
while True:
yield tuple(map(next, iterators))


When my_zip is called, it just creates an infinite loop and never terminates. If I insert a print statement (like shown below), it is revealed that my_zip is infinitely yielding empty tuples!

def my_zip(*iterables):
iterators = tuple(map(iter, iterables))
while True:
t = tuple(map(next, iterators))
print(t)
yield t


However, the equivalent code with a generator expression works fine:

def my_genexp_zip(*iterables):
iterators = tuple(iter(it) for it in iterables)
while True:
try:
yield tuple(next(it) for it in iterators)
except:
print("exception caught!")
return


Why is the function with map not behaving as expected? (Or, if it is expected behavior, how could I modify its behavior to match that of the function using the generator expression?)

I am testing with the following code:

print(list(my_genexp_zip(range(5), range(0, 10, 2))))
print(list(my_zip(range(5), range(0, 10, 2))))

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