An error occurred while evaluating expression: EMS_J_PROJECT_MEETING.PROJECT_ID:cast( 'type!{urn:com:appian:types:EMS}EMS_J_PROJECT_MEETING'("PROJECT_ID"), pv!PROJECT_ID) (Expression evaluation error at function 'cast':

while i am trying to map a process variable which is a forigen key in another table, i got an an error saying that  integer cannot be cast into the datatype "EMS_DATATYPE", so i thought to cast it , but my cast is showing the same error ...

this  is the code that i written in scrip task

cast(
  'type!{urn:com:appian:types:EMS}EMS_J_PROJECT_MEETING'("PROJECT_ID"),
  pv!PROJECT_ID
)

and the error is

An error occurred while evaluating expression: EMS_J_PROJECT_MEETING.PROJECT_ID:cast(
   'type!{urn:com:appian:types:EMS}EMS_J_PROJECT_MEETING'("PROJECT_ID"),
   
pv!PROJECT_ID
) (Expression evaluation error at function 'cast': Could not cast from EMS_J_PROJECT_MEETING to Number (Integer). Details: CastInvalid) (Data Outputs)

any suggestions?