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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 read_egginfo_json(pkg_name, filename=DEFAULT_JSON, working_set=None):
 """ Read json from egginfo of a package identified by `pkg_name` that's already installed within the current Python environment. """


    working_set = working_set or default_working_set
    dist = find_pkg_dist(pkg_name, working_set=working_set)
    return read_dist_egginfo_json(dist, filename)