def __init__(self, f, format='xml'):
        self.format = format
        self.fields, self.dynamic_fields, self.default_field_name, self.unique_key \
            = self.schema_parse(f)
        self.default_field = self.fields[self.default_field_name] \
            if self.default_field_name else None
        self.unique_field = self.fields[self.unique_key] \
            if self.unique_key else None
        self.dynamic_field_cache = {}
initialize a schema object from a
dataset/ETHPy150Open tow/sunburnt/sunburnt/schema.py/SolrSchema.__init__