text: def get_dna(dna, x, y):
      if x > len(dna)-1:
          return None
      line = dna[x]
      if y > len(line)-1:
          return None
      char_dna = line[y]
      return char_dna
  
  def check(dna,
            x1, y1,
            x2, y2,
            x3, y3,
            x4, y4
            ):
      curr = get_dna(dna, x1, y1)
      print("curr: " + curr)
      result = (curr == get_dna(dna, x2, y2)) and (curr == get_dna(dna, x3, y3)) and (curr == get_dna(dna, x4, y4))
      if result:
          print("result found! "+str(x1)+" "+str(y1))
      return result
  
  def match(dna, x, y):
      # limites do array!!
      right = check(dna,
                    x, y,
                    x, y+1,
                    x, y+2,
                    x, y+3)
      if right:
          return True
      down = check(dna,
                    x, y,
                    x+1, y,
                    x+2, y,
                    x+3, y)
      if down:
          return True
      dleft = check(dna,
                    x, y,
                    x-1, y+1,
                    x-2, y+2,
                    x-3, y+3)
      if dleft:
          return True
      dright = check(dna,
                    x, y,
                    x+1, y+1,
                    x+2, y+2,
                    x+3, y+3)
      if dright:
          return True
  
  def mutants(dna):
      if not isinstance(dna, list):
          print("Not a list")
          return False
      # para cada linha
      for x in range(len(dna)):
          line = dna[x]
          # para letra cada linha
          for y in range(len(line)):
              # verifica se bate com o padrao
              is_match = match(dna, x, y)
              if is_match:
                  return True
      return False
  
  def cli(args=None):
      """Process command line arguments."""
      dna = ["CTGAGA",
             "CTGAGC",
             "TATTGT",
             "AGAGAG",
             "CCCCTA",
             "TCACTG"];
      print(mutants(dna));