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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 reload(filename=None, url=r"https://raw.githubusercontent.com/googlei18n/emoji4unicode/master/data/emoji4unicode.xml", loader_class=None):
 u"""reload google's `emoji4unicode` project's xml file. must call this method first to use `e4u` library."""

    if loader_class is None:
        loader_class = loader.Loader
    global _loader
    _loader = loader_class()
    _loader.load(filename, url)