import hashlib

def sha256(data: bytes) -> bytes:
    """Single SHA-256 hash (returns raw bytes)"""
    return hashlib.sha256(data).digest()

def double_sha256(data: bytes) -> str:
    """Bitcoin-style Double SHA-256 hash (returns hex string)"""
    return hashlib.sha256(hashlib.sha256(data).digest()).hexdigest()

# Example input (like a Bitcoin block header or transaction)
data = b"This is example Bitcoin data"

# Apply single SHA-256
single_hash = hashlib.sha256(data).hexdigest()
print("Single SHA-256 Hash:")
print(single_hash)

# Apply double SHA-256
double_hash = double_sha256(data)
print("\nDouble SHA-256 Hash (Bitcoin-style):")
print(double_hash)
