import types

    
def inv(fn):
    import types
    import dis

    t=fn.__code__
    c=list(t.co_code)

    idxs=[]
    i=0
    n=len(c)
    lc=dis.opmap['LOAD_CONST']

    while i<n:
        opcode=ord(c[i])
        if opcode==lc and c[i+1]!='\0':
            idxs+=[i+1]
        i+=1
        if opcode>=dis.HAVE_ARGUMENT:
            i+=2

    for i in range(len(idxs)/2):
        c[idxs[i]], c[idxs[-i-1]] = c[idxs[-i-1]], c[idxs[i]]
    outcode=types.CodeType( t.co_argcount, t.co_nlocals, t.co_stacksize, t.co_flags, ''.join(c), t.co_consts, t.co_names, t.co_varnames, t.co_filename, t.co_name, t.co_firstlineno, t.co_lnotab)
    return types.FunctionType(outcode, globals(), fn.__name__[::-1])

@inv
def f():
    print 'Line1'
    print 'Line2'
    print 'Line3'
    print 'Line4'

f()