code: def has_option_with_value(self, prefix, actual_arguments=True):
          
          if actual_arguments:
              args = self.actual_arguments
          else:
              args = self.formal_arguments
          for arg in [arg for arg in args if (arg is not None) and (arg.startswith(prefix + u"="))]:
              lis = arg.split(u"=")
              if len(lis) >= 2:
                  return u"=".join(lis[1:])
          return None
docs: Check if the actual arguments include an option
          starting with the given ``prefix`` and having a value,
          e.g. ``--format=ogg`` for ``prefix="--format"``.
  
          :param prefix: the option prefix
          :type  prefix: Unicode string
          :param actual_arguments: if ``True``, check among actual arguments;
                                   otherwise check among formal arguments
          :rtype actual_arguments: bool
          :rtype: Unicode string or None