code: def find(expression, schema=None):
      '''
      Gets an <expression> and optional <schema>.
      <expression> should be a string of python code.
      <schema> should be a dictionary mapping field names to types.
      '''
      parser = SchemaFreeParser() if schema is None else SchemaAwareParser(schema)
      return parser.parse(expressionf find(expression, schema=None):
      '''
      Gets an <expression> and optional <schema>.
      <expression> should be a string of python code.
      <schema> should be a dictionary mapping field names to types.
      '''
      parser = SchemaFreeParser() if schema is None else SchemaAwareParser(schema)
      return parser.parse(expression)
docs: Gets an <expression> and optional <schema>.
      <expression> should be a string of python code.
      <schema> should be a dictionary mapping field names to types.