code: def __construct_from_components(self, ns_uri, prefix=None, schema_location=None):
          
  
          assert ns_uri  # other fields are optional
  
          self.uri = ns_uri
          self.schema_location = schema_location or None
          self.prefixes = OrderedSet()
  
          if prefix:
              self.prefixes.add(prefix)
          self.preferred_prefix = prefix or None
docs: Initialize this instance from a namespace URI, and optional
          prefix and schema location URI.