You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: session.go
    path of file: ./repos/iris/sessions
    
    the code of the file until where you have to start completion: package sessions

import (
	"reflect"
	"strconv"
	"sync"

	"github.com/kataras/iris/v12/core/memstore"
)

type (
	// Session should expose the Sessions's end-user API.
	// It is the session's storage controller which you can
	// save or retrieve values based on a key.
	//
	// T
    
func (s *Session) GetFloat64(key string) (float64, error) {
	v := s.Get(key)

	if vfloat32, ok := v.(float32); ok {
		return float64(vfloat32), nil
	}

	if vfloat64, ok := v.(float64); ok {
		return vfloat64, nil
	}

	if vint, ok := v.(int); ok {
		return float64(vint), nil
	}

	if vint64, ok := v.(int64); ok {
		return float64(vint64), nil
	}

	if vstring, sok := v.(string); sok {
		return strconv.ParseFloat(vstring, 32)
	}

	return -1, newErrEntryNotFound(key, reflect.Float64, v)
}