Checks whether a program is available on the shell PATH.

def check_program(self, name):
        """
        Checks whether a program is available on the shell PATH.
        
        """
        if not check_program(name):
            raise management.CommandError(
                "The program \"{name:s}\" is not available in the shell. "
                "Please ensure that \"{name:s}\" is installed and reachable "
                "through your PATH environment variable.".format(
                    name=name))