Inline functions: unable to call a function containing : symbol in code

create function func1() {(select 'beer' from system:dual)}

create function external_func() {(select distinct(type) from `beer-sample` where type=get_type())}

select external_func()

select distinct(type) from `beer-sample` where type='beer'

 select get_type()

[

 {

 "code": 5010,

 "msg": "Error evaluating projection. - cause: Could not decode body function definition for get_type because syntax error - at : - cause: syntax error - at :"

 }

]