def __init__(self, file_path, filesystem, side_effect=None):
        """
        Args:
            file_path: Path to the existing file.
            filesystem: The fake filesystem where the file is created.

        Raises:
            OSError: if the file does not exist in the real file system.
            OSError: if the file already exists in the fake file system.
        """
        super(FakeFileFromRealFile, self).__init__(
            name=os.path.basename(file_path), filesystem=filesystem,
            side_effect=side_effect)
        self.contents_read = False
def __init__ ( self , file_path , filesystem , side_effect = None ) : super ( FakeFileFromRealFile , self ) . __init__ ( name = os . path . basename ( file_path ) , filesystem = filesystem , side_effect = side_effect ) self . contents_read = False
Args:
            file_path: Path to the existing file.
            filesystem: The fake filesystem where the file is created.

        Raises:
            OSError: if the file does not exist in the real file system.
            OSError: if the file already exists in the fake file system.