How to use one function which can be accessed for all schemas

Hi,

I have several schemas in my database, I want to create just one function to use with all these schema.

I create the function in a main schema then the trigger call the function and error occurs : "No function matches the given name and argument types. You might need to add explicit type casts."

How to use just one function which can  be work amongst all shemas in the db ?

My objective is to reduce update of functions code just once not for many schemas. I dont want to duplicate my functions for each schema.

Thanks