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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _add_arg_python(self, key, value=None, mask=False):
 """Add CLI Arg formatted specifically for Python. Args: key (string):
 The CLI Args key (e.g., --name). value (string):
 The CLI Args value (e.g., bob). mask (boolean, default:False):
 Indicates whether no mask value. """

        self._data[key] = value
        if not value:
            # both false boolean values (flags) and empty values should not be added.
            pass
        elif value is True:
            # true boolean values are flags and should not contain a value
            self._args.append('--{}'.format(key))
            self._args_quoted.append('--{}'.format(key))
            self._args_masked.append('--{}'.format(key))
        else:
            self._args.append('--{}={}'.format(key, value))
            if mask:
                # mask sensitive values
                value = 'x' * len(str(value))
            else:
                # quote all values that would get displayed
                value = self.quote(value)
            self._args_quoted.append('--{}={}'.format(key, value))
            self._args_masked.append('--{}={}'.format(key, value))