'Add another member to the array.
Args:
value: The new data to append to the array.
**kwarg:  Create a new element from these keywords.
Returns:
The value which was added. This can be modified further by the caller and
changes will be propagated here.
Raises:
ValueError: If the value to add is not allowed.'

def Append(self, value=None, **kwarg):

    if (self.rdf_type is not None):
        if (isinstance(value, rdfvalue.RDFValue) and (value.__class__ != self.rdf_type)):
            raise ValueError(('Can    only    accept    %s' % self.rdf_type))
        try:
            value = self.rdf_type(value, **kwarg)
        except (TypeError, ValueError):
            raise ValueError(('Unable    to    initialize    %s    from    type    %s' % (self.__class__.__name__, type(value))))
    self.content.Append(DataBlob().SetValue(value))
