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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_file(name, directory):
 """Searches up from a directory looking for a file"""

    path_bits = directory.split(os.sep)
    for i in range(0, len(path_bits) - 1):
        check_path = path_bits[0:len(path_bits) - i]
        check_file = "%s%s%s" % (os.sep.join(check_path), os.sep, name)
        if os.path.exists(check_file):
            return abspath(check_file)

    return None