def _explode(lines, indent):
    """Split each line in `lines` at tabstops

    Tabstops at the beginning of each line are expanded to 2 spaces.

    Return list of rows (a row being a list of strings, i.e. cells)
    """
    exploded = []
    for line in lines:
        indentions = 0
        while line.startswith('\t'):
            indentions += 1
            line = line[1:]
        splitline = line.split('\t')
        for i in range(indentions):
            splitline.insert(0, ' ' * indent)
        exploded.append(splitline)
    return exploded
