'Copies plural forms header contents from a Django catalog of locale to
the msgs string, inserting it at the right place. msgs should be the
contents of a newly created .po file.'

def copy_plural_forms(self, msgs, locale):

    django_dir = os.path.normpath(os.path.join(os.path.dirname(django.__file__)))
    if (self.domain == 'djangojs'):
        domains = ('djangojs', 'django')
    else:
        domains = ('django',)
    for domain in domains:
        django_po = os.path.join(django_dir, 'conf', 'locale', locale, 'LC_MESSAGES', ('%s.po' % domain))
        if os.path.exists(django_po):
            with io.open(django_po, 'rU', encoding='utf-8') as fp:
                m = plural_forms_re.search(fp.read())
            if m:
                plural_form_line = force_str(m.group('value'))
                if (self.verbosity > 1):
                    self.stdout.write(('copying    plural    forms:    %s\n' % plural_form_line))
                lines = []
                found = False
                for line in msgs.split('\n'):
                    if ((not found) and ((not line) or plural_forms_re.search(line))):
                        line = ('%s\n' % plural_form_line)
                        found = True
                    lines.append(line)
                msgs = '\n'.join(lines)
                break
    return msgs
