code: def _get_file_content(source):
      
      filepath = os.path.join('siglists', source + '.txt')
  
      lines = []
      with resource_stream(__name__, filepath) as f:
          for i, line in enumerate(f):
              line = line.decode('utf-8', 'strict').strip()
              if not line or line.startswith('#'):
                  continue
  
              try:
                  re.compile(line)
              except Exception as ex:
                  raise BadRegularExpressionLineError(
                      'Regex error: {} in file {} at line {}'.format(
                          str(ex),
                          filepath,
                          i
                      )
                  )
  
              lines.append(line)
  
      if source in _SPECIAL_EXTENDED_VALUES:
          lines = lines + _SPECIAL_EXTENDED_VALUES[source]
  
      return tuple(lines)
docs: Return a tuple, each value being a line of the source file.
  
      Remove empty lines and comments (lines starting with a '#').