import time

# Measure the excution time of a given function
def time_decorator(func):
  def wrapper(*args, **kwargs):
    begin_time = time.time()
    output = func(*args, **kwargs)
    end_time = time.time()
    print(f"Execution time of function {func.__name__}: {round(end_time - begin_time, 2)} seconds.")
    return output
  return wrapper

# Categorize the total amount of each transaction
@time_decorator
def group_txn_price(data):
  for txn in data:
    price = txn['totalAmt']
    if 0 <= price <= 1500:
      txn['totalAmtCat'] = 'Low'
    elif 1500 < price <= 3500:
      txn['totalAmtCat'] = 'Moderate'
    elif 3500 < price:
      txn['totalAmtCat'] = 'High'
    return data

txn_list = group_txn_price(txn_list)

# Output
# Execution time of function group_txn_price: 0.26 seconds.