Trying to write to .bash_profile for postgres user from python script run as root [duplicate]

So I am writing a programme in python3 which will install postgreSQL on the local host.

I am trying to configure some parameters in the .bash_profile file using the below code

import subprocess;
import os;
import pwd;

db_version = '15.0'
db_version_short = (str(db_version)).split('.')[0]

def runcmd(cmd, verbose = False, *args, **kwargs):

    process = subprocess.Popen(
        cmd,
        stdout = subprocess.PIPE,
        stderr = subprocess.PIPE,
        shell = True
    )
    std_out, std_err = process.communicate()
    if verbose:
        print((std_out.strip()).decode('utf-8'), std_err)
    pass


#########


stdoutdata = subprocess.getoutput("sudo -u postgres echo ~")
print("stdout: " + (stdoutdata.split()[0]) + '\n')
homedir = (stdoutdata.split()[0])

print(homedir)

os.chdir(homedir)

#clear contents of existing bash profile
runcmd('> .bash_profile', verbose= True)


# Define the lines to write in the .bash_profile file
bash_lines = [f"export PGDATA=/db/pgdata/{db_version_short}/data",
            f"export LD_LIBRARY_PATH=/db/pgbin/{db_version_short}/lib",
            "export PGPORT=5432",
            f"export PGSQL=/db/pgbin/pgsql/{db_version_short}",
            "PATH=$PATH:$PGSQL/bin;export PATH",
            "LANG=en_US.UTF-8; export LANG;"]

# Join the lines with line breaks
bash_command = "\n".join(bash_lines)

write_command = "sudo -u postgres echo '{}' >> {}/.bash_profile".format(bash_command,homedir)

runcmd(write_command, verbose= True)

The problem I am having is that when I am running this script as root, it is trying to write to /root/.bash_profile instead of to /home/postgres/.bash_profile.

Anyone have any ideas of how I could set homedir to the postgres user's home directory?

I tried running the script but it keeps setting homedir to /root, when I want it to be /home/postgres/