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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 add_showcases(self, showcases, showcases_to_check=None):
 # type: (List[Union[hdx.data.showcase.Showcase,Dict,str]], List[hdx.data.showcase.Showcase]) -> bool """Add dataset to multiple showcases Args: showcases (List[Union[Showcase,Dict,str]]):
 A list of either showcase ids or showcase metadata from Showcase objects or dictionaries showcases_to_check (List[Showcase]):
 list of showcases against which to check existence of showcase. Defaults to showcases containing dataset. Returns: bool: True if all showcases added or False if any already present """

        if showcases_to_check is None:
            showcases_to_check = self.get_showcases()
        allshowcasesadded = True
        for showcase in showcases:
            if not self.add_showcase(showcase, showcases_to_check=showcases_to_check):
                allshowcasesadded = False
        return allshowcasesadded