from typing import Sequence


def isPalindromicList(L: Sequence) -> bool:
    """Check if a list is palindromic."""
    for i in range(len(L) // 2):
        if L[i] != L[-i - 1]:
            return False
    return True


print("Testing isPalindromicList()...", end="")
assert isPalindromicList([1, 2, 2, 1]) == True
assert isPalindromicList([1, 2, 3, 1]) == False
assert isPalindromicList([1]) == True
assert isPalindromicList([5.0, -1, True, "hey", True, -1, 5.0]) == True
assert isPalindromicList([0, "hi", False, False, 4.0]) == False
assert isPalindromicList([]) == True

# Verify function is non-mutating
L = [1, 2, 1]
assert isPalindromicList(L) == True
assert L == [1, 2, 1]

L = [1, 9, 8]
assert isPalindromicList(L) == False
assert L == [1, 9, 8]
print("Passed!")