symbolic links, aliases, cls clear

[mp]

i have a python program which attempts to call 'cls' but fails:

sh: line 1: cls: command not found

i tried creating an alias from cls to clear in .profile, .cshrc, and
/etc/profile, but none of these options seem to work.

my conclusion is that a python program that is executing does not use
the shell (because it does not recognize shell aliases). is this
correct?

should i use a symbolic link? if so, where should i place it?

what is the difference between aliases and symbolic links?

if i execute a command like 'clear' to clear the screen, where does the
shell look to find the command 'clear'?

i'm using os x.

thanks
mp