human
I wrote the below code

    class BlockTranslateParser(TokenParser, ):
        def top(self):
            countervar = None
            counter = None
            extra_context = {}
            while self.more():
                tag = self.tag()
                if ((tag == 'with') or (tag == 'and')):
                    value = self.value()
                    if (self.tag() != 'as'):
                        raise TemplateSyntaxError("variable    bindings    in    'blocktrans'    must    be    'with    value    as    variable'")
                    extra_context[self.tag()] = VariableNode(parser.compile_filter(value))
                elif (tag == 'count'):
                    counter = parser.compile_filter(self.value())
                    if (self.tag() != 'as'):
                        raise TemplateSyntaxError("counter    specification    in    'blocktrans'    must    be    'count    value    as    variable'")
                    countervar = self.tag()
                else:
                    raise TemplateSyntaxError(("unknown    subtag    %s    for    'blocktrans'    found" % tag))
            return (countervar, counter, extra_context)
    (countervar, counter, extra_context) = BlockTranslateParser(token.contents).top()
    singular = []
    plural = []
    while parser.tokens:
        token = parser.next_token()
        if (token.token_type in (TOKEN_VAR, TOKEN_TEXT)):
            singular.append(token)
        else:
            break
    if (countervar and counter):
        if (token.contents.strip() != 'plural'):
            raise TemplateSyntaxError("'blocktrans'    doesn't    allow    other    block    tags    inside    it")
        while parser.tokens:
            token = parser.next_token()
            if (token.token_type in (TOKEN_VAR, TOKEN_TEXT)):
                plural.append(token)
            else:
                break
    if (token.contents.strip() != 'endblocktrans'):
        raise TemplateSyntaxError(("'blocktrans'    doesn't    allow    other    block    tags    (seen    %r)    inside    it" %...

What's a good function header?
assistant
#Here's a good function header.

def do_block_translate(parser, token):