def count_keys(n):
return [bin(j)[<NUM_LIT:2>:].zfill(n) for j in range(<NUM_LIT:2>**n)]<EOL>
Generate outcome bitstrings for n-qubits.

    Args:
        n (int): the number of qubits.

    Returns:
        list: A list of bitstrings ordered as follows:
        Example: n=2 returns ['00', '01', '10', '11'].