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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 aside_view_declaration(self, view_name):
 """ Find and return a function object if one is an aside_view for the given view_name Aside methods declare their view provision via @XBlockAside.aside_for(view_name) This function finds those declarations for a block. Arguments: view_name (string):
 the name of the view requested. Returns: either the function or None """

        if view_name in self._combined_asides:  # pylint: disable=unsupported-membership-test
            return getattr(self, self._combined_asides[view_name])  # pylint: disable=unsubscriptable-object
        else:
            return None