<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def from_job_desc(cls, warm_start_config):
 """Creates an instance of ``WarmStartConfig`` class, from warm start configuration response from DescribeTrainingJob. Args: warm_start_config (dict):
 The expected format of the ``warm_start_config`` contains two first-class fields: * "type": Type of warm start tuner, currently two supported types - "IdenticalDataAndAlgorithm" and "TransferLearning". * "parents": List of tuning job names from which the warm start should be done. Returns: sagemaker.tuner.WarmStartConfig: De-serialized instance of WarmStartConfig containing the type and parents provided as part of ``warm_start_config``. Examples: "TransferLearning" ["p1","p2"] """

        if not warm_start_config or \
                WARM_START_TYPE not in warm_start_config or \
                PARENT_HYPERPARAMETER_TUNING_JOBS not in warm_start_config:
            return None

        parents = []
        for parent in warm_start_config[PARENT_HYPERPARAMETER_TUNING_JOBS]:
            parents.append(parent[HYPERPARAMETER_TUNING_JOB_NAME])

        return cls(warm_start_type=WarmStartTypes(warm_start_config[WARM_START_TYPE]),
                   parents=parents)