'EnvVarsPostProcessor constructor.
Args:
vars_map: Dictionary of "string" -> "string|list", i.e. a mapping of
environment variables names to their suggested values or to lists
of their suggested values.'

def __init__(self, vars_map):

    super(core.PostProcessor, self).__init__()
    self.vars_map = {}
    for (var_name, value) in vars_map.items():
        var_regex = re.compile(re.escape((('%' + var_name) + '%')), flags=re.IGNORECASE)
        self.vars_map[var_name.lower()] = (var_regex, value)
