code: def get_aggregate_function_type(self, agg_func_name):
      agg_func_type = None
      if agg_func_name == "COUNT":
          agg_func_type = ExpressionType.AGGREGATION_COUNT
      elif agg_func_name == "MIN":
          agg_func_type = ExpressionType.AGGREGATION_MIN
      elif agg_func_name == "MAX":
          agg_func_type = ExpressionType.AGGREGATION_MAX
      elif agg_func_name == "SUM":
          agg_func_type = ExpressionType.AGGREGATION_SUM
      elif agg_func_name == "AVG":
          agg_func_type = ExpressionType.AGGREGATION_AVG
      elif agg_func_name == "FIRST":
          agg_func_type = ExpressionType.AGGREGATION_FIRST
      elif agg_func_name == "LAST":
          agg_func_type = ExpressionType.AGGREGATION_LAST
      elif agg_func_name == "SEGMENT":
          agg_func_type = ExpressionType.AGGREGATION_SEGMENT
      return agg_func_type
  
file_path: evadb/evadb/parser/lark_visitor/_functions.py
imports: from lark import Token, Tree
  from evadb.expression.abstract_expression import ExpressionType
  from evadb.expression.aggregation_expression import AggregationExpression
  from evadb.expression.constant_value_expression import ConstantValueExpression
  from evadb.expression.function_expression import FunctionExpression
  from evadb.expression.tuple_value_expression import TupleValueExpression
  from evadb.parser.create_function_statement import CreateFunctionStatement
label_desc: Use image node_id 4 for calling the Functions obj's underlying member method code with example usage: obj.get_aggregate_function_type(agg_func_name) and returns: agg_func_type