code: def _get_dict_param(self, param_prefix):
          
          params = {}
          for key, value in self.querystring.items():
              if key.startswith(param_prefix):
                  params[camelcase_to_underscores(
                      key.replace(param_prefix, ""))] = value[0]
          return params
docs: Given a parameter dict of
          {
              'Instances.SlaveInstanceType': ['m1.small'],
              'Instances.InstanceCount': ['1']
          }
  
          returns
          {
              "SlaveInstanceType": "m1.small",
              "InstanceCount": "1",
          }