def row_empty_spaces(row, puzzle):
    """
    Takes a row number, and a sudoku puzzle as parameter
    Returns a list of empty spaces in that row on the puzzle
    """
    valid_spaces = []
    for col in range(0, 9):
        if puzzle[row][col] == -1:
            valid_spaces.append([row, col])
    i = 1
    print("\nThere are {} available spaces on your selected row.".format(len(valid_spaces)))
    for space in valid_spaces:
        print("Space Number", str(i), ": ", space)
        i += 1
    return valid_spaces