systemjs/base.py
def trace(self, app):
        """
        Trace the dependencies for app.

        A tracer-instance is shortlived, and re-tracing the same app should
        yield the same results. Since tracing is an expensive process, cache
        the result on the tracer instance.
        """
        if app not in self._trace_cache:
            process = subprocess.Popen(
                "trace-deps.js {}".format(app), shell=True,
                stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                env=self.env, universal_newlines=True, cwd=self._package_json_dir
            )
            out, err = process.communicate()
            if err:
                raise TraceError(err)
            self._trace_cache[app] = json.loads(out)
        return self._trace_cache[app]
def trace(self, app):
        if app not in self._trace_cache:
            process = subprocess.Popen(
                "trace-deps.js {}".format(app), shell=True,
                stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                env=self.env, universal_newlines=True, cwd=self._package_json_dir
            )
            out, err = process.communicate()
            if err:
                raise TraceError(err)
            self._trace_cache[app] = json.loads(out)
        return self._trace_cache[app]
def trace ( self , app ) : if app not in self . _trace_cache : process = subprocess . Popen ( "trace-deps.js {}" . format ( app ) , shell = True , stdout = subprocess . PIPE , stderr = subprocess . PIPE , env = self . env , universal_newlines = True , cwd = self . _package_json_dir ) out , err = process . communicate ( ) if err : raise TraceError ( err ) self . _trace_cache [ app ] = json . loads ( out ) return self . _trace_cache [ app ]
Trace the dependencies for app.

        A tracer-instance is shortlived, and re-tracing the same app should
        yield the same results. Since tracing is an expensive process, cache
        the result on the tracer instance.
Trace the dependencies for app .