# tf.compat.v1.flags.mark_flag_as_required

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Ensures that flag is not None during program execution.

    tf.compat.v1.flags.mark_flag_as_required(
        flag_name, flag_values=_flagvalues.FLAGS
    )

Registers a flag validator, which will follow usual validator rules.
Important note: validator will pass for any non-`None` value, such as
`False`, `0` (zero), `''` (empty string) and so on.

If your module might be imported by others, and you only wish to make the flag
required when the module is directly executed, call this method like this::

    if __name__ == '__main__':
      flags.mark_flag_as_required('your_flag_name')
      app.run()

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| ## Args ||
|---|---|
| `flag_name` | str \| FlagHolder, name or holder of the flag. Positional-only parameter. |
| `flag_values` | flags.FlagValues, optional :class:`~absl.flags.FlagValues` instance where the flag is defined. |

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| ## Raises ||
|---|---|
| `AttributeError` | Raised when flag_name is not registered as a valid flag name. |
| `ValueError` | Raised when flag_values is non-default and does not match the FlagValues of the provided FlagHolder instance. |

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