'Deletes the specified environment variable.
Does nothing if the environment variable is not set.
Starting from Robot Framework 2.7, it is possible to remove multiple
variables by passing them to this keyword as separate arguments.'

def remove_environment_variable(self, *names):

    for name in names:
        value = del_env_var(name)
        if value:
            self._info(("Environment    variable    '%s'    deleted." % name))
        else:
            self._info(("Environment    variable    '%s'    does    not    exist." % name))
