you can use a mutable data type for this, ie list
just create a list, define it's size if you want list_ = [None for i in range(4)]
and then with index you can add sublist inside it of any length like
list_[1] = [1,2,3,4,]
# list_ = [None, [1,2,3,4], None, None]
or you can create an empty list list_ =[]
and add the sublist using append operation like
list_.append([1,2,3])
#list_ = [[1,2,3]]
in later stage if you want to overwrite the sublist, you can directly do that by assigning the index to new sublist ie list_[2] = [1,2,3,]
listobject. Python containers (and in general) are heterogenous, you can put whatever type of object you want in them