Ensures complex property types have the correct default values

def get_default_for(prop, value):
    """ Ensures complex property types have the correct default values """

    prop = prop.strip('_')     # Handle alternate props (leading underscores)
    val = reduce_value(value)  # Filtering of value happens here

    if prop in _COMPLEX_LISTS:
        return wrap_value(val)
    elif prop in _COMPLEX_STRUCTS:
        return val or {}
    else:
        return u'' if val is None else val