code: def get_symbol(self) -> str:
      if self.etype == ExpressionType.LOGICAL_AND:
          return "AND"
      elif self.etype == ExpressionType.LOGICAL_OR:
          return "OR"
      elif self.etype == ExpressionType.LOGICAL_NOT:
          return "NOT"
      else:
          raise NotImplementedError
  
file_path: evadb/evadb/expression/logical_expression.py
imports: from evadb.expression.abstract_expression import AbstractExpression, ExpressionReturnType, ExpressionType
label_desc: Use image node_id 4 for calling the LogicalExpression obj's underlying member method code with example usage: obj.get_symbol() and returns: str, str, str