Returns a command that prepends the given paths to the named path variable on
        the current platform.

def prepend_path_variable_command(variable, paths):
    """
        Returns a command that prepends the given paths to the named path variable on
        the current platform.
    """
    assert isinstance(variable, basestring)
    assert is_iterable_typed(paths, basestring)
    return path_variable_setting_command(
        variable, paths + [expand_variable(variable)])