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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 dest_fpath(self, source_fpath: str) -> str: """Calculates full path for end json-api file from source file full path."""

        relative_fpath = os.path.join(*source_fpath.split(os.sep)[1:])
        relative_dirpath = os.path.dirname(relative_fpath)

        source_fname = relative_fpath.split(os.sep)[-1]
        base_fname = source_fname.split('.')[0]
        dest_fname = f'{base_fname}.json'

        return os.path.join(self.dest_dir, relative_dirpath, dest_fname)