alias inside a script returns command not found

Using bash in a Debian system.

bash --version
GNU bash, version 4.4.12(1)-release (x86_64-pc-linux-gnu)
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

I defined an alias inside a function. I use this alias to write to a log file. Since I run this command as non-privileged user, I'm using tee to do this: alias is not found.

I get:

./test.sh 
Preparing Environment...
/tmp/support/20200525_074655
./test.sh: line 19: WRITE_LOG: command not found
./test.sh: line 20: ifconfig: command not found
./test.sh: line 20: WRITE_LOG: command not found

test.sh

#!/bin/bash


function prepare_environment() {
    echo "Preparing Environment..."
    TICKET_ID=$(date '+%Y%m%d_%H%M%S')
    LOG_LOCATION=/tmp/support/"${TICKET_ID}"
    sudo mkdir -p "${LOG_LOCATION}" 
    echo "${LOG_LOCATION}"
    alias WRITE_LOG='sudo tee -a "${LOG_LOCATION}"/report.log  > /dev/null'
}

function write_log() {
    sudo tee -a "${LOG_LOCATION}"/report.log  > /dev/null
}


function collect_information() {
    echo "Current Report time: $(date '+%Y/%m/%d %H:%M.%S')" | WRITE_LOG
    ifconfig | WRITE_LOG
}   

prepare_environment
echo "Current Report time: $(date '+%Y/%m/%d %H:%M.%S')" | write_log
collect_information

Alternatives:

• I have various commands, instead of doing sudo command > file.log I though this would be a cleaner way to do it.
• I can do sudo command | write_log

Similar question