How to use the setupmeta.trace function in setupmeta

"""
    :param str root: Path to project folder
    :return setupmeta.scm.Scm: SCM used by project, if any
    """
    if os.environ.get(setupmeta.SCM_DESCRIBE):
        return Snapshot(root)

    scm_root = find_scm_root(os.path.abspath(root), ".git")
    if scm_root:
        return Git(scm_root)

    version_file = os.path.join(root, setupmeta.VERSION_FILE)
    if os.path.isfile(version_file):
        return Snapshot(root)

    setupmeta.trace("could not determine SCM for '%s'" % root)
    return None

"""
        :param str|None setup_py_path: Given setup.py (when invoked from test)
        """
        if not setup_py_path:
            # Determine path to setup.py module from call stack
            for frame in inspect.stack():
                module = inspect.getmodule(frame[0])
                if module and is_setup_py_path(module.__file__):
                    setup_py_path = module.__file__
                    trace("setup.py found from call stack: %s" % setup_py_path)
                    break

        if not setup_py_path and sys.argv:
            if is_setup_py_path(sys.argv[0]):
                setup_py_path = sys.argv[0]
                trace("setup.py found from sys.argv: %s" % setup_py_path)

        if is_setup_py_path(setup_py_path):
            setup_py_path = os.path.abspath(setup_py_path)
            MetaDefs.project_dir = os.path.dirname(setup_py_path)
            trace("project dir: %s" % MetaDefs.project_dir)

return

        vdef = self.meta.definitions.get("version")
        if vdef and vdef.source and vdef.source.lower().endswith("-info"):
            # We already got version from PKG-INFO
            return

        cv = vdef.sources[0].value if vdef and vdef.sources else None
        if self.problem:
            if not cv:
                self.meta.auto_fill("version", "0.0.0", "missing")

            if self.strategy:
                setupmeta.warn(self.problem)

            setupmeta.trace("not auto-filling version due to problem: [%s]" % self.problem)
            return

        gv = self.scm.get_version()
        if self.generate_version_file:
            path = setupmeta.project_path(setupmeta.VERSION_FILE)
            with open(path, "w") as fh:
                fh.write("%s" % gv)

        if gv.patch and "patch" not in self.strategy.bumpable:
            msg = "patch version component should be .0 for versioning strategy '%s', " % self.strategy
            msg += "'.%s' from current version tag '%s' will be ignored" % (gv.patch, gv)
            setupmeta.warn(msg)

        rendered = self.strategy.rendered(gv)
        if cv and gv:
            cvc = setupmeta.version_components(cv)

given = meta.value("versioning")
        self.strategy = Strategy.from_meta(given)
        self.enabled = bool(given and self.strategy and not self.strategy.problem)
        self.scm = scm
        self.generate_version_file = scm and scm.root != setupmeta.MetaDefs.project_dir and not os.environ.get(setupmeta.SCM_DESCRIBE)
        self.problem = None
        if not self.strategy:
            self.problem = "setupmeta versioning not enabled"

        elif self.strategy.problem:
            self.problem = self.strategy.problem

        elif not self.scm:
            self.problem = "project not under a supported SCM"

        setupmeta.trace("versioning given: '%s', strategy: [%s], problem: [%s]" % (given, self.strategy, self.problem))

def merge_sources(self, sources):
        """ Record the fact that we saw this definition in 'sources' """
        for entry in sources:
            if not self.value and entry.value:
                self.value = entry.value
                trace("[-- %s] %s=%s" % (entry.source, self.key, entry.value))
            self.sources.append(entry)

def auto_fill_version(self):
        """
        Auto-fill version as defined by self.strategy
        :param setupmeta.model.SetupMeta meta: Parent meta object
        """
        pygradle_version = os.environ.get("PYGRADLE_PROJECT_VERSION")
        if pygradle_version:
            # Minimal support for https://github.com/linkedin/pygradle
            self.meta.auto_fill("version", pygradle_version, "pygradle", override=True)
            return

        if not self.enabled:
            setupmeta.trace("not auto-filling version, versioning is disabled")
            return

        vdef = self.meta.definitions.get("version")
        if vdef and vdef.source and vdef.source.lower().endswith("-info"):
            # We already got version from PKG-INFO
            return

        cv = vdef.sources[0].value if vdef and vdef.sources else None
        if self.problem:
            if not cv:
                self.meta.auto_fill("version", "0.0.0", "missing")

            if self.strategy:
                setupmeta.warn(self.problem)

            setupmeta.trace("not auto-filling version due to problem: [%s]" % self.problem)

def find_project_dir(self, setup_py_path):
        """
        :param str|None setup_py_path: Given setup.py (when invoked from test)
        """
        if not setup_py_path:
            # Determine path to setup.py module from call stack
            for frame in inspect.stack():
                module = inspect.getmodule(frame[0])
                if module and is_setup_py_path(module.__file__):
                    setup_py_path = module.__file__
                    trace("setup.py found from call stack: %s" % setup_py_path)
                    break

        if not setup_py_path and sys.argv:
            if is_setup_py_path(sys.argv[0]):
                setup_py_path = sys.argv[0]
                trace("setup.py found from sys.argv: %s" % setup_py_path)

        if is_setup_py_path(setup_py_path):
            setup_py_path = os.path.abspath(setup_py_path)
            MetaDefs.project_dir = os.path.dirname(setup_py_path)
            trace("project dir: %s" % MetaDefs.project_dir)