'Add a new identity to the given JID/node combination.
Each identity must be unique in terms of all four identity
components: category, type, name, and language.
Multiple, identical category/type pairs are allowed only
if the xml:lang values are different. Likewise, multiple
category/type/xml:lang pairs are allowed so long as the
names are different. A category and type is always required.
Arguments:
category -- The identity\'s category.
itype    -- The identity\'s type.
name     -- Optional name for the identity.
lang     -- Optional two-letter language code.
node     -- The node to modify.
jid      -- The JID to modify.'

def add_identity(self, category='', itype='', name='', node=None, jid=None, lang=None):

    kwargs = {'category': category, 'itype': itype, 'name': name, 'lang': lang}
    self.api['add_identity'](jid, node, None, kwargs)
