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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 load_tag_library(libname):
 """ Load a templatetag library on multiple Django versions. Returns None if the library isn't loaded. """

    from django.template.backends.django import get_installed_libraries
    from django.template.library import InvalidTemplateLibrary
    try:
        lib = get_installed_libraries()[libname]
        lib = importlib.import_module(lib).register
        return lib
    except (InvalidTemplateLibrary, KeyError):
        return None