def checkifvalid(board, column):
    """
    Takes input parameters board and column
    Checks if move is valid by checking for vacanciesin that column.
    Returns True if move is valid
    """
    valid = False  # just checks if there are any empty spaces in the column
    for j in range(6):
        if board[j][column] == 0:
            valid = True
    return valid