Remove a level of indentation from python code

dedent.py

from tokenize import generate_tokens, untokenize, INDENT, DEDENT

def dedent_python(codestr):
    """Remove the first level of indentation from a block of python code"""

    indent = None
    level = 0
    tokens = []
    lines = codestr.splitlines(True)
    for toknum, tokval, _, _, _ in generate_tokens(iter(lines).next):
        if toknum == INDENT:
            level += 1
            if level == 1:
                indent = tokval
                continue
            else:
                tokval = level * indent
        elif toknum == DEDENT:
            level -= 1
            if level == 0:
                continue
        tokens.append((toknum, tokval))
    return untokenize(tokens)