def prebuild_action(instance):
walker_map = {<EOL>'<STR_LIT>': FunctionPrebuilder,<EOL>'<STR_LIT>': BridgePrebuilder,<EOL>'<STR_LIT>': OperationPrebuilder,<EOL>'<STR_LIT>': DerivedAttributePrebuilder,<EOL>'<STR_LIT>': TransitionPrebuilder,<EOL>'<STR_LIT>': RequiredOperationPrebuilder,<EOL>'<STR_LIT>': RequiredSignalPrebuilder,<EOL>'<STR_LIT>': ProvidedOperationPrebuilder,<EOL>'<STR_LIT>': ProvidedSignalPrebuilder<EOL>}<EOL>metaclass = xtuml.get_metaclass(instance)<EOL>walker = walker_map[metaclass.kind](metaclass.metamodel, instance)<EOL>logger.info('<STR_LIT>' % walker.label)<EOL>root = oal.parse(instance.Action_Semantics_internal)<EOL>return walker.accept(root)<EOL>
Transform textual OAL actions of an *instance* to instances in the ooaofooa
subsystems Value and Body. The provided *instance* must be an instance of 
one of the following classes:

- S_SYNC
- S_BRG
- O_TFR
- O_DBATTR
- SM_ACT
- SPR_RO
- SPR_RS
- SPR_PO
- SPR_PS