enumerate(sequence) returns an iterator that provides tuples with two elements: the position of an element in the sequence (that is: the index) and the corresponding value:
someList = ['foo', 'bar', 'baz']
enumeratedList = enumerate(someList)
print (type(enumeratedList))
# <class 'enumerate'>
for index, element in enumeratedList:
print("{:d}: {:s}".format(index, element) )
# 0: foo
# 1: bar
# 2: baz