# tf.errors.OperatorNotAllowedInGraphError

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| [![](https://www.tensorflow.org/images/GitHub-Mark-32px.png) View source on GitHub](https://github.com/tensorflow/tensorflow/blob/v2.13.1/tensorflow/python/framework/errors_impl.py#L34-L54) |

Raised when an unsupported operator is present in Graph execution.

    tf.errors.OperatorNotAllowedInGraphError(
        *args, **kwargs
    )

For example, using a [`tf.Tensor`](https://www.tensorflow.org/versions/r2.13/api_docs/python/tf/Tensor) as a Python `bool` inside a Graph will
raise `OperatorNotAllowedInGraphError`. Iterating over values inside a
[`tf.Tensor`](https://www.tensorflow.org/versions/r2.13/api_docs/python/tf/Tensor) is also not supported in Graph execution.

#### Example:

    @tf.function
    def iterate_over(t):
      a,b,c = t
      return a

    iterate_over(tf.constant([1, 2, 3]))
    Traceback (most recent call last):

    OperatorNotAllowedInGraphError: ...