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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 whereis(self, channel):
 """ get ocurrences of channel name in the file Parameters channel : str channel name string Returns ------- ocurrences : tuple Examples -------- ((1, 2), (2, 4)) () """

        if channel in self:
            return tuple(self.channels_db[channel])
        else:
            return tuple()