3 calls to options_array_flatten()

list_field_validate in modules/field/modules/list/list.module: Implements hook_field_validate().
_options_get_options in modules/field/modules/options/options.module: Collects the options for a field.
_options_storage_to_form in modules/field/modules/options/options.module: Transforms stored field values into the format the widgets need.

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