I'm trying to work out evapotranspiration from climate data based on the Hargreaves Samani methodology using this package

The data I'm working on in csv format is available here and the code I'm using (with comments) is below

## Using Evapotranspiration package to get DAILY PE ### require(Evapotranspiration) require(zoo) #load the constants required from the Evapotranspiration package data("constants") #converting the CSV to a zoo object OakPark<- read.csv("OakParkR.csv", header=TRUE) #Fill the blanks in the csv with NAs na.fill(OakPark,NA) #convert to a zoo OakPark <- as.zoo(OakPark) #create a zoo series with the required variables PE.data <- OakPark[ ,c(3,5)] #converting to a list as ET function works on a list PE.data <- as.list(PE.data) #change constants to the local values constants$Elev = 62 constants$lat_rad = 0.9226 #defining the function funname <- "HargreavesSamani" class(PE.data) <- funname #creating a new variable with the calculation results <- ET(PE.data,constants)

The error then reads:

Error: length(time(x)) == length(by[[1]]) is not TRUE

I've looked at other help sections such as this but can't see how I can implement this for it to work on this built-in HargreavesSamani function.