Get the value of an option in the config file.

    Args:
      section: string, the section of the config file to check.
      option: string, the option to retrieve the value of.

    Returns:
      string, the value of the option or None if the option doesn't exist.

def GetOptionString(self, section, option):
    """Get the value of an option in the config file.

    Args:
      section: string, the section of the config file to check.
      option: string, the option to retrieve the value of.

    Returns:
      string, the value of the option or None if the option doesn't exist.
    """
    if self.config.has_option(section, option):
      return self.config.get(section, option)
    else:
      return None