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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 write(self, s: str) -> None: """Add str to internal bytes buffer and if echo is True, echo contents to inner stream"""

        if not isinstance(s, str):
            raise TypeError('write() argument must be str, not {}'.format(type(s)))

        if not self.pause_storage:
            self.buffer.byte_buf += s.encode(encoding=self.encoding, errors=self.errors)
        if self.echo:
            self.inner_stream.write(s)