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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 process_runway_configs(runway_dir=''):
 """Read the _application.json_ files. Args: runway_dir (str):
 Name of runway directory with app.json files. Returns: collections.defaultdict: Configurations stored for each environment found. """

    LOG.info('Processing application.json files from local directory "%s".', runway_dir)
    file_lookup = FileLookup(runway_dir=runway_dir)
    app_configs = process_configs(file_lookup, 'application-master-{env}.json', 'pipeline.json')
    return app_configs