def returns_lists(cells=16, actions=4):
    """Initialize returns list. Each state has four possible actions.

    Args:
        cells ([type]): Array with cells in grid
        actions ([type]): Array with possible actions

    Returns:
        [type]: Rewards dictionary
    """
    # Each state has four possible actions to take
    def create_array(n, lst):
        for i in range(n):
            lst.append(str(i))
        return lst

    possible_states = []
    possible_states = create_array(cells, possible_states)

    possible_actions = []
    possible_actions = create_array(actions, possible_actions)

    returns = {}
    for state in possible_states:
        for action in possible_actions:
            returns[state+", "+action] = []

    return returns