Answer for ROSALIND Open Reading Frames https://rosalind.info/problems/orf/

 import re  
 condon_len = 3  
 c_map = {  
   "A":"T",  
   "G":"C",  
   "C":"G",  
   "T":"A"  
 }  
 dna_map = {  
   "TTT":"F", "TCT":"S", "TAT":"Y", "TGT":"C",   
 "TTC":"F", "TCC":"S", "TAC":"Y", "TGC":"C",   
 "TTA":"L", "TCA":"S", "TAA":"STOP", "TGA":"STOP",   
 "TTG":"L", "TCG":"S", "TAG":"STOP", "TGG":"W",   
 "CTT":"L", "CCT":"P", "CAT":"H", "CGT":"R",   
 "CTC":"L", "CCC":"P", "CAC":"H", "CGC":"R",   
 "CTA":"L", "CCA":"P", "CAA":"Q", "CGA":"R",   
 "CTG":"L", "CCG":"P", "CAG":"Q", "CGG":"R",   
 "ATT":"I", "ACT":"T", "AAT":"N", "AGT":"S",   
 "ATC":"I", "ACC":"T", "AAC":"N", "AGC":"S",   
 "ATA":"I", "ACA":"T", "AAA":"K", "AGA":"R",   
 "ATG":"M", "ACG":"T", "AAG":"K", "AGG":"R",   
 "GTT":"V", "GCT":"A", "GAT":"D", "GGT":"G",   
 "GTC":"V", "GCC":"A", "GAC":"D", "GGC":"G",   
 "GTA":"V", "GCA":"A", "GAA":"E", "GGA":"G",   
 "GTG":"V", "GCG":"A", "GAG":"E", "GGG":"G"  
 }  
 found = []  
 input_file = open("rosalind_orf.txt", "r")  
 def GetComplement(seq):  
   r = ''.join([c_map[x] for x in seq])  
   return r  
 def GetAA(condon):  
   return dna_map[condon]  
 def GetAASeq(dna_seq, pos):  
   dna_seq_len = len(dna_seq)  
   seq=""  
   start_pos = pos  
   end_pos = pos + condon_len  
   condon = dna_seq[start_pos:end_pos]  
   AA = GetAA(condon)  
   while AA != "STOP":  
     seq = seq + AA  
     start_pos = start_pos + condon_len  
     end_pos = end_pos + condon_len  
     if (end_pos> (dna_seq_len-1)):  
       return "" #end of seq reached without finding stop condon  
     condon = dna_seq[start_pos:end_pos]  
     AA = GetAA(condon)  
   found.append(seq)    
   return seq    
 dna_seq = ""  
 lines = input_file.readlines()  
 for l in lines:  
   if (l[0]!=">"):  
     dna_seq = dna_seq + l.replace("\n", "").replace("\r","")  
 r_dna_seq = GetComplement(dna_seq[::-1])  
 seq_regex="ATG"  
 p = re.compile(seq_regex)  
 for m in p.finditer(dna_seq):  
   GetAASeq(dna_seq, m.start())  
 for m in p.finditer(r_dna_seq):  
   GetAASeq(r_dna_seq, m.start())    
 for s in list(set(found)):  
   print(s)