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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 render_descriptor(data):
 """Render data descriptor. The rendering is based on descriptor schema and input context. :param data: data instance :type data: :class:`resolwe.flow.models.Data` or :class:`dict` """

    if not data.descriptor_schema:
        return

    # Set default values
    for field_schema, field, path in iterate_schema(data.descriptor, data.descriptor_schema.schema, 'descriptor'):
        if 'default' in field_schema and field_schema['name'] not in field:
            dict_dot(data, path, field_schema['default'])