):

main.py

@@ -4,13 +4,15 @@ def get_tx_count(tx_list):
     Input: List of transaction IDs (strings)
     Output: Integer count
     """
+    return len(tx_list)
 
 def filter_large_txids(tx_list, min_length):
     """
     TODO: Return a list of txids with length greater than or equal to min_length.
     Input: List of txids (strings), minimum length (int)
     Output: Filtered list of strings
     """
+    return [txid for txid in tx_list if len(txid) >= min_length]
 
 def process_txids(tx_list):
     """
@@ -19,6 +21,7 @@ def process_txids(tx_list):
     Input: List of txids (strings)
     Output: List of (int, string) tuples
     """
+    return [(i, txid) for i, txid in enumerate(tx_list) if txid.startswith("tx")]
 
 def example_while_loop(limit):
     """
@@ -27,13 +30,23 @@ def example_while_loop(limit):
     Input: Integer limit
     Output: List of integers
     """
+    result = []
+    i = 0
+    while i < limit:
+        if i == 5:
+            break
+        result.append(i)
+        i += 1
+    return result
 
 def unpack_tuple(block_header):
     """
     TODO: Unpack the tuple representing a Bitcoin block header (height, previous hash, timestamp).
     Input: Tuple (int, str, int)
     Output: Unpacked tuple values
     """
+    height, prev_hash, timestamp = block_header
+    return height, prev_hash, timestamp
 
 def dict_methods_example(block):
     """
@@ -42,13 +55,16 @@ def dict_methods_example(block):
     Input: Dict
     Output: Tuple of (list, list, list)
     """
+    return list(block.keys()), list(block.values()), list(block.items())
 
 def multiple_assignment(a, b):
     """
     TODO: Demonstrate multiple assignments and swapping two variables.
     Input: two integers
     Output: Tuple of two ints (swapped)
     """
+    a, b = b, a
+    return a, b
 
 def set_example(addresses):
     """
@@ -57,46 +73,57 @@ def set_example(addresses):
     Input: List of strings
     Output: Set of strings
     """
+    return set(addresses)
 
 
 class BitcoinTransaction:
     def __init__(self, txid, amount):
         """
         TODO: Initialize transaction with txid (string) and amount (float).
         """
+        self.txid = txid
+        self.amount = amount
 
     def __str__(self):
         """
         TODO: Return string representation: "Tx {txid} of {amount} BTC"
         """
+        return f"Tx {self.txid} of {self.amount} BTC"
 
 class Wallet:
     def __init__(self):
         """
         TODO: Initialize an empty list to hold transactions.
         """
+        self.transactions = []
 
     def add_tx(self, tx):
         """
         TODO: Add a BitcoinTransaction to the wallet's transaction list.
         """
+        self.transactions.append(tx)
 
     def total_balance(self):
         """
         TODO: Calculate and return the sum of amounts of all transactions.
         Output: Float
         """
-
+        return sum(tx.amount for tx in self.transactions)
 
 def txid_generator(tx_list):
     """
     TODO: Yield each txid from the list one by one.
     Input: List of strings
     """
+    for txid in tx_list:
+        yield txid
 
 def filter_txids_gen(tx_list, prefix="tx"):
     """
     TODO: Yield txids from list that start with given prefix.
     Default prefix is 'tx'.
     Input: List of strings, prefix string
     """
+    for txid in tx_list:
+        if txid.startswith(prefix):
+            yield txid