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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 fix_addresses(start=None, end=None):
 """Set missing addresses to start and end of IDB. Take a start and end addresses. If an address is None or `BADADDR`, return start or end addresses of the IDB instead. Args start: Start EA. Use `None` to get IDB start. end: End EA. Use `None` to get IDB end. Returns: (start, end) """

    if start in (None, idaapi.BADADDR):
        start = idaapi.cvar.inf.minEA

    if end in (None, idaapi.BADADDR):
        end = idaapi.cvar.inf.maxEA

    return start, end