def apply_sparse_attention(self, attention):
    """
    Applies sparse attention mechanism to the input data.

    This function is a placeholder for the actual implementation of sparse attention.
    It should take input tensors and apply a sparse attention mechanism to them.

    Returns:
        None
    """
    window_size = 2
    N, heads, query_len, key_len = attention.shape
    for i in range(N):
        for h in range(heads):
            for q in range(query_len):
                start = max(0, q - window_size)
                end = min(key_len, q + window_size)
                attention[i, h, q, :start] = 0
                attention[i, h, q, end:] = 0
    return attention