code: def list_available_providers(self):
          
          providers = []
  
          if self.alternative_config_dir:
              for f in os.listdir(os.path.join(self.alternative_config_dir, self.CLOUD_PROVIDERS_DIR)):
                  if os.path.splitext(f)[1] in ['.conf', '.json']:
                      try:
                          n = os.path.join(self.alternative_config_dir, self.CLOUD_PROVIDERS_DIR, f)
                          providers.append(ServiceProviderConfiguration(n))
                      except ControllerConfigurationException:
                          pass
  
  
          for f in os.listdir(os.path.join(self.default_config_dir, self.CLOUD_PROVIDERS_DIR)):
              if os.path.splitext(f)[1] in ['.conf', '.json']:
                  try:
                      n = os.path.join(self.default_config_dir, self.CLOUD_PROVIDERS_DIR, f)
                      providers.append(ServiceProviderConfiguration(n))
                  except ControllerConfigurationException:
                      pass
  
          return providers
docs: Lists all the ServiceProvider configuration files found in the configuration folders
          :return: