def _dedentlines(lines, tabsize=8, skip_first_line=False):
    DEBUG = False
    if DEBUG: 
        print "dedent: dedent(..., tabsize=%d, skip_first_line=%r)"\
              % (tabsize, skip_first_line)
    indents = []
    margin = None
    for i, line in enumerate(lines):
        if i == 0 and skip_first_line: continue
        indent = 0
        for ch in line:
            if ch == ' ':
                indent += 1
            elif ch == '\t':
                indent += tabsize - (indent % tabsize)
            elif ch in '\r\n':
                continue # skip all-whitespace lines
            else:
                break
        else:
            continue # skip all-whitespace lines
        if DEBUG: print "dedent: indent=%d: %r" % (indent, line)
        if margin is None:
            margin = indent
        else:
            margin = min(margin, indent)
    if DEBUG: print "dedent: margin=%r" % margin

    if margin is not None and margin > 0:
        for i, line in enumerate(lines):
            if i == 0 and skip_first_line: continue
            removed = 0
            for j, ch in enumerate(line):
                if ch == ' ':
                    removed += 1
                elif ch == '\t':
                    removed += tabsize - (removed % tabsize)
                elif ch in '\r\n':
                    if DEBUG: print "dedent: %r: EOL -> strip up to EOL" % line
                    lines[i] = lines[i][j:]
                    break
                else:
                    raise ValueError("unexpected non-whitespace char %r in "
                                     "line %r while removing %d-space margin"
                                     % (ch, line, margin))
                if DEBUG:
                    print "dedent: %r: %r -> removed %d/%d"\
                          % (line, ch, removed, margin)
                if removed == margin:
                    lines[i] = lines[i][j+1:]
                    break
                elif removed > margin:
                    lines[i] = ' '*(removed-margin) + lines[i][j+1:]
                    break
            else:
                if removed:
                    lines[i] = lines[i][removed:]
    return lines
_dedentlines(lines, tabsize=8, skip_first_line=False) -> dedented lines
dataset/ETHPy150Open CollabQ/CollabQ/vendor/markdown/markdown2.py/_dedentlines