def role(name)
      json = client.get("/v1/auth/approle/role/#{encode_path(name)}")
      return Secret.decode(json)
    rescue HTTPError => e
      return nil if e.code == 404
      raise
    end
def role(name)
      json = client.get("/v1/auth/approle/role/#{encode_path(name)}")
      return Secret.decode(json)
    rescue HTTPError => e
      return nil if e.code == 404
      raise
    end
Gets the AppRole by the given name. If an AppRole does not exist by that
 name, +nil+ is returned.

 @example
   Vault.approle.role("testrole") #=> #<Vault::Secret lease_id="...">

 @return [Secret, nil]