private static string GenerateAuthToken(string client_id = null, string client_secret = null) {
AdmAccessToken admToken;
string headerValue;
// Checks if azure login info is overriden
client_id = client_id == null ? azure_client_id : client_id;
client_secret = client_secret == null ? azure_client_secret : client_secret;
AdmAuthentication admAuth = new AdmAuthentication(client_id, client_secret);
admToken = admAuth.GetAccessToken();
DateTime tokenReceived = DateTime.Now;
// Create a header with the access_token property of the returned token
headerValue = "Bearer " + admToken.access_token;
// Return header
return headerValue;
}