code: def _gen_txt_data(self, f):
  		
  		reader = iter(f)
  
  		for line_num, line in enumerate(reader):
  			if line_num == 0 and self.has_header:
  				continue
  
  			datum = line.rstrip('\r\n')
  
  			yield datum, line_num+1
docs: Yields (line, line number) tuples from the given file handler. Skips
  		the first line if the self.has_header flag is set.
  
  		Helper for the gen_ipa_data method.