<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_commands(filename, class_name, language):
 """ Generate the related compilation and execution commands. Parameters :param filename : str The used filename. :param class_name : str The used class name. :param language : {'c', 'go', 'java', 'js', 'php', 'ruby'} The target programming language. Returns ------- comp_cmd, exec_cmd : (str, str) The compilation and execution command. """

        cname = str(class_name)
        fname = str(filename)
        lang = str(language)

        # Compilation variants:
        comp_vars = {
            # gcc brain.c -o brain
            'c': 'gcc {} -lm -o {}'.format(fname, cname),
            # javac Brain.java
            'java': 'javac {}'.format(fname),
            # go build -o brain brain.go
            'go': 'go build -o {} {}.go'.format(cname, cname)
        }
        comp_cmd = comp_vars.get(lang, None)

        # Execution variants:
        exec_vars = {
            # ./brain
            'c': os.path.join('.', cname),
            # java -classpath . Brain
            'java': 'java -classpath . {}'.format(cname),
            # node brain.js
            'js': 'node {}'.format(fname),
            # php -f Brain.php
            'php': 'php -f {}'.format(fname),
            # ruby brain.rb
            'ruby': 'ruby {}'.format(fname),
            # ./brain
            'go': os.path.join('.', cname),
        }
        exec_cmd = exec_vars.get(lang, None)

        return comp_cmd, exec_cmd