i have a type mismatch error can you please help me fix this code
type Customer = {
Id: int
IsVip: bool
Credit: decimal
}
let getPurchases (customer: Customer) =
if customer.Id % 2 = 0 then
120.0M
else
80.0M
let tryPromoteToVip (customer: Customer) =
if getPurchases customer > 100.0M then
{ customer with IsVip = true }
else
customer
let increaseCreditIfVip (customer: Customer) =
if customer.IsVip then
{ customer with Credit = customer.Credit + 100.0M }
else
{ customer with Credit = customer.Credit + 50.0M }
let upgradeCustomerProcedural customer =
let purchases = getPurchases customer
let customer2 = tryPromoteToVip customer
increaseCreditIfVip customer2
let upgradeCustomerNested customer =
increaseCreditIfVip (tryPromoteToVip (customer |> getPurchases))
let upgradeCustomerComposed = getPurchases >> tryPromoteToVip >> increaseCreditIfVip
let upgradeCustomerPiped customer =
customer
|> tryPromoteToVip
|> increaseCreditIfVip
|> getPurchases
let customerVIP = { Id = 1; IsVip = true; Credit = 0.0M }
let customerSTD = { Id = 2; IsVip = false; Credit = 100.0M }
let assertVIP = upgradeCustomerComposed customerVIP = { Id = 1; IsVip = true; Credit = 100.0M
}
let assertSTDtoVIP = upgradeCustomerComposed customerSTD = { Id = 2; IsVip = true; Credit =
200.0M }
let assertSTD = upgradeCustomerComposed { customerSTD with Id = 3; Credit = 50.0M } = { Id =
3; IsVip = false; Credit = 100.0M }.
