<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def pprint(self, composites):
 """ Print out a nicely indented Mapfile """


        # if only a single composite is used then cast to list
        # and allow for multiple root composites

        if composites and not isinstance(composites, list):
            composites = [composites]

        lines = []

        for composite in composites:
            type_ = composite["__type__"]
            if type_ in ("metadata", "validation"):
                # types are being parsed directly, and not as an attr of a parent
                lines += self.process_key_dict(type_, composite, level=0)
            else:
                lines += self._format(composite)

        result = str(self.newlinechar.join(lines))
        return result