code: def parse_genotypes(self, lb, ub):
          
          file = self.openfile(self.current_file)
          words = file.readline().strip().split()[lb:ub]
          word_count = len(words)
          idx =0
  
          if word_count > 0:
              dosages = numpy.empty((self.ind_count, word_count), dtype='|S5')
              while word_count > 1:
                  dosages[idx] = numpy.array(words)
                  idx += 1
                  line = file.readline()
                  words = line.strip().split()[lb:ub]
                  word_count = len(words)
          else:
              raise EOFError
  
          return dosages
docs: Extracts a fraction of the file (current chunk of loci) loading
          the genotypes into memoery.
  
          :param lb: Lower bound of the current chunk
          :param ub: Upper bound of the current chunk
          :return: Dosage dosages for current chunk