How to use the base58.b58decode_chk function in base58

def is_valid(v):
    '''Check vector v for validity'''
    result = b58decode_chk(v)
    if result is None:
        return False
    valid = False
    for template in templates:
        prefix = str(bytearray(template[0]))
        suffix = str(bytearray(template[2]))
        if result.startswith(prefix) and result.endswith(suffix):
            if (len(result) - len(prefix) - len(suffix)) == template[1]:
                return True
    return False

def is_valid(v):
    '''Check vector v for validity'''
    result = b58decode_chk(v)
    if result is None:
        return False
    for template in templates:
        prefix = str(bytearray(template[0]))
        suffix = str(bytearray(template[2]))
        if result.startswith(prefix) and result.endswith(suffix):
            if (len(result) - len(prefix) - len(suffix)) == template[1]:
                return True
    return False

def is_valid(v):
    '''Check vector v for validity'''
    result = b58decode_chk(v)
    if result is None:
        return False
    for template in templates:
        prefix = str(bytearray(template[0]))
        suffix = str(bytearray(template[2]))
        if result.startswith(prefix) and result.endswith(suffix):
            if (len(result) - len(prefix) - len(suffix)) == template[1]:
                return True
    return False

def is_valid(v):
    '''Check vector v for validity'''
    result = b58decode_chk(v)
    if result is None:
        return False
    valid = False
    for template in templates:
        prefix = str(bytearray(template[0]))
        suffix = str(bytearray(template[2]))
        if result.startswith(prefix) and result.endswith(suffix):
            if (len(result) - len(prefix) - len(suffix)) == template[1]:
                return True
    return False

def is_valid(v):
    '''Check vector v for validity'''
    result = b58decode_chk(v)
    if result is None:
        return False
    for template in templates:
        prefix = str(bytearray(template[0]))
        suffix = str(bytearray(template[2]))
        if result.startswith(prefix) and result.endswith(suffix):
            if (len(result) - len(prefix) - len(suffix)) == template[1]:
                return True
    return False

def is_valid(v):
    '''Check vector v for validity'''
    result = b58decode_chk(v)
    if result is None:
        return False
    valid = False
    for template in templates:
        prefix = str(bytearray(template[0]))
        suffix = str(bytearray(template[2]))
        if result.startswith(prefix) and result.endswith(suffix):
            if (len(result) - len(prefix) - len(suffix)) == template[1]:
                return True
    return False

def is_valid(v):
    '''Check vector v for validity'''
    result = b58decode_chk(v)
    if result is None:
        return False
    for template in templates:
        prefix = str(bytearray(template[0]))
        suffix = str(bytearray(template[2]))
        if result.startswith(prefix) and result.endswith(suffix):
            if (len(result) - len(prefix) - len(suffix)) == template[1]:
                return True
    return False

# A valid address is a RIPEMD-160 hash which contains 20 bytes
    # Prior to base58 encoding 1 version byte is prepended and
    # 4 checksum bytes are appended so the total number of
    # base58 encoded bytes should be 25.  This means the number of characters
    # in the encoding should be about 34 ( 25 * log2( 256 ) / log2( 58 ) ).
    dash_version = 140 if network == 'testnet' else 76

    # Check length (This is important because the base58 library has problems
    # with long addresses (which are invalid anyway).
    if ((len(address) < 26) or (len(address) > 35)):
        return False

    address_version = None

    try:
        decoded = base58.b58decode_chk(address)
        address_version = ord(decoded[0:1])
    except:
        # rescue from exception, not a valid Dash address
        return False

    if (address_version != dash_version):
        return False

    return True

# A valid address is a RIPEMD-160 hash which contains 20 bytes
    # Prior to base58 encoding 1 version byte is prepended and
    # 4 checksum bytes are appended so the total number of
    # base58 encoded bytes should be 25.  This means the number of characters
    # in the encoding should be about 34 ( 25 * log2( 256 ) / log2( 58 ) ).
    axe_version = 140 if network == 'testnet' else 76

    # Check length (This is important because the base58 library has problems
    # with long addresses (which are invalid anyway).
    if ((len(address) < 26) or (len(address) > 35)):
        return False

    address_version = None

    try:
        decoded = base58.b58decode_chk(address)
        address_version = ord(decoded[0:1])
    except:
        # rescue from exception, not a valid Axe address
        return False

    if (address_version != axe_version):
        return False

    return True