public override string ToString()
{
StringBuilder builder = new StringBuilder();
builder.Append(_term);
builder.Append(" => [");
foreach (Posting posting in _postings.Values)
{
builder.Append(posting.ToString());
builder.Append(", ");
}
if (builder.Length > 1)
{
builder.Remove(builder.Length-2, 2);
}
builder.Append("]");
return builder.ToString();
}
}