IndentationError: unexpected unindent WHY?

Question

IndentationError: unexpected unindent WHY???

#!/usr/bin/python import sys class Seq:     def __init__(self, id, adnseq, colen):         self.id     = id         self.dna    = adnseq         self.cdnlen = colen         self.prot   = ""     def __str__(self):         return ">%s\n%s\n" % (self.id, self.prot)     def translate(self, transtable):         self.prot = ""         for i in range(0,len(self.dna),self.cdnlen):             codon = self.dna[i:i+self.cdnlen]             aa    = transtable[codon]             self.prot += aa     def parseCommandOptions(cmdargs):         tfname = cmdargs[1]         sfname = cmdargs[2]         return (tfname, sfname)     def readTTable(fname):         try:             ttable = {}             cdnlen = -1             tfile = open(fname, "r")             for line in tfile:                 linearr = line.split()                 codon   = linearr[0]                 cdnlen  = len(codon)                 aa      = linearr[1]                 ttable[codon] = aa             tfile.close()             return (ttable, cdnlen)     def translateSData(sfname, cdnlen, ttable):         try:              sequences = []             seqf = open(seq_fname, "r")             line = seqf.readline()             while line:                 if line[0] == ">":                     id = line[1:len(line)].strip()                     seq = ""                     line = seqf.readline()                     while line and line[0] != '>':                         seq += line.strip()                         line = seqf.readline()                       sequence = Seq(id, seq, cdnlen)                     sequence.translate(ttable)                     sequences.append(sequence)             seqf.close()             return sequences         if __name__ == "__main__":         (trans_table_fname, seq_fname) = parseCommandOptions(sys.argv)         (transtable, colen) = readTTable(trans_table_fname)         seqs = translateSData(seq_fname, colen, transtable)         for s in seqs:             print s 

It says:

 def translateSeqData(sfname, cdnlen, ttable):    ^ IndentationError: unexpected unindent 

WHY? I have checked a thousands times and I can't find the problem. I have only used Tabs and no spaces. Plus, sometimes it asks to define the class. Is that Ok?

Answer 1

It's because you have:

def readTTable(fname):     try: 

without a matching except block after the try: block. Every try must have at least one matching except.

See the Errors and Exceptions section of the Python tutorial.

Answer 2

you didn't complete your try statement. You need and except in there too.