[Python] How can I check if I can fetch data from an iterable object several times?

Simple method which prints elements from some source two times:

def p2(source):
for x in source:
print(x)
for x in source:
print(x)


This method works as expected if the source is a list. But if the source is an iterator or generator this would not work.

>>> p2(x*x for x in [1, 2, 3])
1
4
9


The second for loop would try to fetch data from the already exhausted generator and would not fetch any items from it.

Of course, to fix this problem I can first fetch all the elements from the source into a list and then print elements from this list:

def p2_v2(source):
local_storage = [x for x in source]
for x in local_storage:
print(x)
for x in local_storage:
print(x)


But in case the source argument is already a list creation of an additional list looks like an unnecessary overhead.

How can I check if I can fetch objects from the source several times?

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