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# "undefined symbol: PyUnicodeUCS4\_..." or "undefined symbol: PyUnicodeUCS2\_..." errors

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This error means there is a mismatch between the byte size of Unicode characters used by the environment used to build the wrappers and the environment used to run them. [Read this](https://docs.python.org/2/faq/extending.html#when-importing-module-x-why-do-i-get-undefined-symbol-pyunicodeucs2) for more information.

If this error occured when using python environments with [pyenv](https://github.com/pyenv/pyenv/), you can simply reinstall the python version used to run the tests with the required Unicode character size. For example, if your Python version was `2.7.16` and you received the `undefined symbol: PyUnicodeUCS2_` error when running the samples, execute:

{% tabs %}
{% tab title="Shell" %}
{% code lineNumbers="true" %}

```sh
pyenv uninstall 2.7.16
```

{% endcode %}
{% endtab %}
{% endtabs %}

followed by

{% tabs %}
{% tab title="Shell" %}
{% code lineNumbers="true" %}

```sh
PYTHON_CONFIGURE_OPTS="--enable-unicode=ucs2" pyenv install 2.7.16
```

{% endcode %}
{% endtab %}
{% endtabs %}

then set your [pyenv](https://github.com/pyenv/pyenv/) environment to `2.7.16` and rerun the samples.


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