def write(self, data):
        """Write data to the file. There is no return value.

        `data` can be either a string of bytes or a file-like object
        (implementing :meth:`read`). If the file has an
        :attr:`encoding` attribute, `data` can also be a
        :class:`unicode` (:class:`str` in python 3) instance, which
        will be encoded as :attr:`encoding` before being written.

        Due to buffering, the data may not actually be written to the
        database until the :meth:`close` method is called. Raises
        :class:`ValueError` if this file is already closed. Raises
        :class:`TypeError` if `data` is not an instance of
        :class:`str` (:class:`bytes` in python 3), a file-like object,
        or an instance of :class:`unicode` (:class:`str` in python 3).
        Unicode data is only allowed if the file has an :attr:`encoding`
        attribute.

        :Parameters:
          - `data`: string of bytes or file-like object to be written
            to the file

        .. versionadded:: 1.9
           The ability to write :class:`unicode`, if the file has an
           :attr:`encoding` attribute.
        """
        if self._closed:
            raise ValueError("cannot write to a closed file")

        try:
            # file-like
            read = data.read
        except AttributeError:
            # string
            if not isinstance(data, string_types):
                raise TypeError("can only write strings or file-like objects")
            if isinstance(data, unicode):
                try:
                    data = data.encode(self.encoding)
                except __HOLE__:
                    raise TypeError("must specify an encoding for file in "
                                    "order to write %s" % (text_type.__name__,))
            read = StringIO(data).read

        if self._buffer.tell() > 0:
            # Make sure to flush only when _buffer is complete
            space = self.chunk_size - self._buffer.tell()
            if space:
                to_write = read(space)
                self._buffer.write(to_write)
                if len(to_write) < space:
                    return # EOF or incomplete
            self.__flush_buffer()
        to_write = read(self.chunk_size)
        while to_write and len(to_write) == self.chunk_size:
            self.__flush_data(to_write)
            to_write = read(self.chunk_size)
        self._buffer.write(to_write)
dataset/ETHPy150Open blynch/CloudMemeBackend/gridfs/grid_file.py/GridIn.write