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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 find_config():
 """Find a build cache somewhere in a parent directory."""

    previous = ""
    current = os.getcwd()
    while previous != current:
        check_path = os.path.join(current, "build.cache")
        if os.path.isfile(check_path):
            return check_path
        else:
            previous = current
            current = os.path.dirname(current)
    raise Exception("Can't find build cache")