<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def print_package_versions(self):
 """Print a list of versions of the package this tool comes from, and indicate which version this tool is from."""

        variants = self.context.get_tool_variants(self.tool_name)
        if variants:
            if len(variants) > 1:
                self._print_conflicting(variants)
                return 1
            else:
                from rez.packages_ import iter_packages
                variant = iter(variants).next()
                it = iter_packages(name=variant.name)
                rows = []
                colors = []

                for pkg in sorted(it, key=lambda x: x.version, reverse=True):
                    if pkg.version == variant.version:
                        name = "* %s" % pkg.qualified_name
                        col = heading
                    else:
                        name = "  %s" % pkg.qualified_name
                        col = local if pkg.is_local else None

                    label = "(local)" if pkg.is_local else ""
                    rows.append((name, pkg.path, label))
                    colors.append(col)

                _pr = Printer()
                for col, line in zip(colors, columnise(rows)):
                    _pr(line, col)
        return 0