How to use the mako.util.FastEncodingBuffer function in Mako

def test_fast_buffer_write(self):
        buf = util.FastEncodingBuffer()
        buf.write("string a ")
        buf.write("string b")
        eq_(buf.getvalue(), "string a string b")

generate_magic_comment=True,
            disable_unicode=False,
            strict_undefined=False,
            enable_loop=True,
            reserved_names=frozenset()):
    """Generate module source code given a parsetree node,
      uri, and optional source filename"""

    # if on Py2K, push the "source_encoding" string to be
    # a bytestring itself, as we will be embedding it into
    # the generated source and we don't want to coerce the
    # result into a unicode object, in "disable_unicode" mode
    if not compat.py3k and isinstance(source_encoding, compat.text_type):
        source_encoding = source_encoding.encode(source_encoding)

    buf = util.FastEncodingBuffer()

    printer = PythonPrinter(buf)
    _GenerateRenderMethod(printer,
                          _CompileContext(uri,
                                          filename,
                                          default_filters,
                                          buffer_filters,
                                          imports,
                                          future_imports,
                                          source_encoding,
                                          generate_magic_comment,
                                          disable_unicode,
                                          strict_undefined,
                                          enable_loop,
                                          reserved_names),
                          node)

def _render_error(template, context, error):
    if template.error_handler:
        result = template.error_handler(context, error)
        if not result:
            compat.reraise(*sys.exc_info())
    else:
        error_template = exceptions.html_error_template()
        if context._outputting_as_unicode:
            context._buffer_stack[:] = [
                util.FastEncodingBuffer(as_unicode=True)]
        else:
            context._buffer_stack[:] = [util.FastEncodingBuffer(
                error_template.output_encoding,
                error_template.encoding_errors)]

        context._set_with_template(error_template)
        error_template.render_context(context, error=error)

def _render_error(template, context, error):
    if template.error_handler:
        result = template.error_handler(context, error)
        if not result:
            raise error
    else:
        error_template = exceptions.html_error_template()
        if context._outputting_as_unicode:
            context._buffer_stack[:] = [util.FastEncodingBuffer(unicode=True)]
        else:
            context._buffer_stack[:] = [util.FastEncodingBuffer(
                                            error_template.output_encoding,
                                            error_template.encoding_errors)]

        context._set_with_template(error_template)
        error_template.render_context(context, error=error)

def _render_error(template, context, error):
    if template.error_handler:
        result = template.error_handler(context, error)
        if not result:
            compat.reraise(*sys.exc_info())
    else:
        error_template = exceptions.html_error_template()
        if context._outputting_as_unicode:
            context._buffer_stack[:] = [
                util.FastEncodingBuffer(as_unicode=True)]
        else:
            context._buffer_stack[:] = [util.FastEncodingBuffer(
                error_template.output_encoding,
                error_template.encoding_errors)]

        context._set_with_template(error_template)
        error_template.render_context(context, error=error)

def _push_writer(self):
        """push a capturing buffer onto this Context and return
        the new writer function."""

        buf = util.FastEncodingBuffer()
        self._buffer_stack.append(buf)
        return buf.write

generate_magic_comment=True,
            disable_unicode=False,
            strict_undefined=False,
            enable_loop=True,
            reserved_names=frozenset()):
    """Generate module source code given a parsetree node,
      uri, and optional source filename"""

    # if on Py2K, push the "source_encoding" string to be
    # a bytestring itself, as we will be embedding it into
    # the generated source and we don't want to coerce the
    # result into a unicode object, in "disable_unicode" mode
    if not compat.py3k and isinstance(source_encoding, compat.text_type):
        source_encoding = source_encoding.encode(source_encoding)

    buf = util.FastEncodingBuffer()

    printer = PythonPrinter(buf)
    _GenerateRenderMethod(printer,
                          _CompileContext(uri,
                                          filename,
                                          default_filters,
                                          buffer_filters,
                                          imports,
                                          future_imports,
                                          source_encoding,
                                          generate_magic_comment,
                                          disable_unicode,
                                          strict_undefined,
                                          enable_loop,
                                          reserved_names),
                          node)