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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 hash(self):
 """Hash value based on file name and content"""

        if self._hash is None:
            tohash = [self.path.name]
            # Hash a maximum of ~1MB of the hdf5 file
            tohash.append(hashfile(self.path, blocksize=65536, count=20))
            self._hash = hashobj(tohash)
        return self._hash