How to use the mako.ast.PythonCode function in Mako

def test_locate_identifiers_7(self):
        code = """
import foo.bar
"""
        parsed = ast.PythonCode(code, **exception_kwargs)
        eq_(parsed.declared_identifiers, set(["foo"]))
        eq_(parsed.undeclared_identifiers, set())

def _parse_attributes(self, expressions, nonexpressions):
        undeclared_identifiers = set()
        self.parsed_attributes = {}
        for key in self.attributes:
            if key in expressions:
                expr = []
                for x in re.compile(r'(\${.+?})',
                                    re.S).split(self.attributes[key]):
                    m = re.compile(r'^\${(.+?)}$', re.S).match(x)
                    if m:
                        code = ast.PythonCode(m.group(1).rstrip(),
                                              **self.exception_kwargs)
                        # we aren't discarding "declared_identifiers" here,
                        # which we do so that list comprehension-declared
                        # variables aren't counted.   As yet can't find a
                        # condition that requires it here.
                        undeclared_identifiers = \
                            undeclared_identifiers.union(
                                code.undeclared_identifiers)
                        expr.append('(%s)' % m.group(1))
                    else:
                        if x:
                            expr.append(repr(x))
                self.parsed_attributes[key] = " + ".join(expr) or repr('')
            elif key in nonexpressions:
                if re.search(r'\${.+?}', self.attributes[key]):
                    raise exceptions.CompileException(

self.printer.writeline("from mako import runtime, filters, cache")
        self.printer.writeline("UNDEFINED = runtime.UNDEFINED")
        self.printer.writeline("__M_dict_builtin = dict")
        self.printer.writeline("__M_locals_builtin = locals")
        self.printer.writeline("_magic_number = %s" % repr(MAGIC_NUMBER))
        self.printer.writeline("_modified_time = %s" % repr(time.time()))
        self.printer.writeline("_template_filename=%s" % repr(self.compiler.filename))
        self.printer.writeline("_template_uri=%s" % repr(self.compiler.uri))
        self.printer.writeline("_template_cache=cache.Cache(__name__, _modified_time)")
        self.printer.writeline("_source_encoding=%s" % repr(self.compiler.source_encoding))
        if self.compiler.imports:
            buf = ''
            for imp in self.compiler.imports:
                buf += imp + "\n"
                self.printer.writeline(imp)
            impcode = ast.PythonCode(buf, source='', lineno=0, pos=0, filename='template defined imports')
        else:
            impcode = None
        
        main_identifiers = module_identifiers.branch(self.node)
        module_identifiers.topleveldefs = module_identifiers.topleveldefs.union(main_identifiers.topleveldefs)
        [module_identifiers.declared.add(x) for x in ["UNDEFINED"]]
        if impcode:
            [module_identifiers.declared.add(x) for x in impcode.declared_identifiers]
            
        self.compiler.identifiers = module_identifiers
        self.printer.writeline("_exports = %s" % repr([n.name for n in main_identifiers.topleveldefs.values()]))
        self.printer.write("\n\n")

        if len(module_code):
            self.write_module_code(module_code)

self.printer.writeline("__M_locals_builtin = locals")
        self.printer.writeline("_magic_number = %r" % MAGIC_NUMBER)
        self.printer.writeline("_modified_time = %r" % time.time())
        self.printer.writeline(
                            "_template_filename=%r" % self.compiler.filename)
        self.printer.writeline("_template_uri=%r" % self.compiler.uri)
        self.printer.writeline(
                    "_template_cache=cache.Cache(__name__, _modified_time)")
        self.printer.writeline(
                    "_source_encoding=%r" % self.compiler.source_encoding)
        if self.compiler.imports:
            buf = ''
            for imp in self.compiler.imports:
                buf += imp + "\n"
                self.printer.writeline(imp)
            impcode = ast.PythonCode(
                            buf, 
                            source='', lineno=0, 
                            pos=0, 
                            filename='template defined imports')
        else:
            impcode = None
        
        main_identifiers = module_identifiers.branch(self.node)
        module_identifiers.topleveldefs = \
            module_identifiers.topleveldefs.\
                union(main_identifiers.topleveldefs)
        module_identifiers.declared.add("UNDEFINED")
        if impcode:
            module_identifiers.declared.update(impcode.declared_identifiers)
            
        self.compiler.identifiers = module_identifiers

def undeclared_identifiers(self):
        res = []
        for c in self.function_decl.defaults:
            res += list(ast.PythonCode(c, **self.exception_kwargs).
                        undeclared_identifiers)
        return set(res).union(
            self.filter_args.
            undeclared_identifiers.
            difference(filters.DEFAULT_ESCAPES.keys())
        ).union(
            self.expression_undeclared_identifiers
        ).difference(
            self.function_decl.allargnames
        )

def __init__(self, text, escapes, **kwargs):
        super(Expression, self).__init__(**kwargs)
        self.text = text
        self.escapes = escapes
        self.escapes_code = ast.ArgumentList(escapes, **self.exception_kwargs)
        self.code = ast.PythonCode(text, **self.exception_kwargs)

def __init__(self, text, escapes, **kwargs):
        super(Expression, self).__init__(**kwargs)
        self.text = text
        self.escapes = escapes
        self.escapes_code = ast.ArgumentList(escapes, **self.exception_kwargs)
        self.code = ast.PythonCode(text, **self.exception_kwargs)

def __init__(self, keyword, attributes, **kwargs):
        super(CallTag, self).__init__(keyword, attributes, 
                                    ('args'), ('expr',), ('expr',), **kwargs)
        self.expression = attributes['expr']
        self.code = ast.PythonCode(self.expression, **self.exception_kwargs)
        self.body_decl = ast.FunctionArgs(attributes.get('args', ''), **self.exception_kwargs)

def __init__(self, keyword, attributes, **kwargs):
        super(IncludeTag, self).__init__(
                                    keyword, 
                                    attributes, 
                                    ('file', 'import', 'args'), 
                                    (), ('file',), **kwargs)
        self.page_args = ast.PythonCode(
                                "__DUMMY(%s)" % attributes.get('args', ''),
                                 **self.exception_kwargs)