input: from typing import Dict, List
  
  
  def create_blockchain(initial_data_list: List[Dict[str, str]]) -> Blockchain:
      """
      Creates a basic blockchain system and populates it with the provided initial data list.
      Each entry in the list is a dictionary containing 'timestamp' and 'data' keys.
      The function returns the created Blockchain object.
  
      >>> initial_data = [{'timestamp': '2023-10-01T12:00:00', 'data': 'Genesis Block'}, {'timestamp': '2023-10-02T12:00:00', 'data': 'First Transaction'}]
      >>> chain = create_blockchain(initial_data)
      >>> print(chain.get_chain())
      [
        {
          "index": 0,
          "timestamp": "2023-10-01T12:00:00",
          "data": "Genesis Block",
          "previous_hash": null,
          "hash": "some_hash_here"
        },
        {
          "index": 1,
          "timestamp": "2023-10-02T12:00:00",
          "data": "First Transaction",
          "previous_hash": "first_block_hash",
          "hash": "some_other_hash_here"
        }
      ]
      """
output:     class Blockchain:
          def __init__(self):
              self.chain = []
              self.create_genesis_block()
  
          def create_genesis_block(self):
              genesis_block = {
                  "index": 0,
                  "timestamp": initial_data_list[0]['timestamp'],
                  "data": initial_data_list[0]['data'],
                  "previous_hash": None,
                  "hash": "some_hash_here"
              }
              self.chain.append(genesis_block)
  
          def add_block(self, data):
              previous_block = self.chain[-1]
              new_block = {
                  "index": len(self.chain),
                  "timestamp": data['timestamp'],
                  "data": data['data'],
                  "previous_hash": previous_block['hash'],
                  "hash": "some_other_hash_here"
              }
              self.chain.append(new_block)
  
          def get_chain(self):
              return self.chain
  
      blockchain = Blockchain()
      for data in initial_data_list[1:]:
          blockchain.add_block(data)
  
      return blockchain