How to call Postgresql Array Function in Python

hi , 
i am trying to call the postgresql function which takes array of type integer which deletes the customer record from table . which is 

select delcustumer('{6}')  -- where 6 is the customer id

Now i am trying to call this postgresql function in python and i dont know how to pass array in python here is my python code

i have declared a argv called custid in my python file 

cust =  connection.db_rel ( "select delcustumer('{}')")
return cust

how can i pass my variable custid which is an element of array which postgresql function is taking to this function in python .
i shall be very thankful to you