How to use the azure-storage-common.azure.storage.common.models._unicode_type function in azure-storage-common

def _get_request_body(request_body):
    '''Converts an object into a request body.  If it's None
    we'll return an empty string, if it's one of our objects it'll
    convert it to XML and return it.  Otherwise we just use the object
    directly'''
    if request_body is None:
        return b''

    if isinstance(request_body, bytes) or isinstance(request_body, IOBase):
        return request_body

    if isinstance(request_body, _unicode_type):
        return request_body.encode('utf-8')

    request_body = str(request_body)
    if isinstance(request_body, _unicode_type):
        return request_body.encode('utf-8')

    return request_body

def _encode_base64(data):
    if isinstance(data, _unicode_type):
        data = data.encode('utf-8')
    encoded = base64.b64encode(data)
    return encoded.decode('utf-8')

def _sign_string(key, string_to_sign, key_is_base64=True):
    if key_is_base64:
        key = _decode_base64_to_bytes(key)
    else:
        if isinstance(key, _unicode_type):
            key = key.encode('utf-8')
    if isinstance(string_to_sign, _unicode_type):
        string_to_sign = string_to_sign.encode('utf-8')
    signed_hmac_sha256 = hmac.HMAC(key, string_to_sign, hashlib.sha256)
    digest = signed_hmac_sha256.digest()
    encoded_digest = _encode_base64(digest)
    return encoded_digest

def _get_request_body(request_body):
    '''Converts an object into a request body.  If it's None
    we'll return an empty string, if it's one of our objects it'll
    convert it to XML and return it.  Otherwise we just use the object
    directly'''
    if request_body is None:
        return b''

    if isinstance(request_body, bytes) or isinstance(request_body, IOBase):
        return request_body

    if isinstance(request_body, _unicode_type):
        return request_body.encode('utf-8')

    request_body = str(request_body)
    if isinstance(request_body, _unicode_type):
        return request_body.encode('utf-8')

    return request_body