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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 get_search_field_values(contentitem):
 """ Extract the search fields from the model. """

    plugin = contentitem.plugin
    values = []
    for field_name in plugin.search_fields:
        value = getattr(contentitem, field_name)

        # Just assume all strings may contain HTML.
        # Not checking for just the PluginHtmlField here.
        if value and isinstance(value, six.string_types):
            value = get_cleaned_string(value)

        values.append(value)

    return values