code: def find_field(item_list, cond, comparator, target_field):
      
      for item in item_list:
          if comparator(item, cond) and target_field in item:
              return item[target_field]
      return None
docs: Finds the value of a field in a dict object that satisfies certain
      conditions.
  
      Args:
          item_list: A list of dict objects.
          cond: A param that defines the condition.
          comparator: A function that checks if an dict satisfies the condition.
          target_field: Name of the field whose value to be returned if an item
              satisfies the condition.
  
      Returns:
          Target value or None if no item satisfies the condition.