anchor.diff:    [<Extension; Obsolete("Use df.ColumnCount")>]
     static member CountColumns(frame:Frame<'R, 'C>) = frame.ColumnIndex.Mappings |> Seq.length
   
  -  /// Filters frame rows using the specified condtion. Returns a new data frame
  +  /// Filters frame rows using the specified condition. Returns a new data frame
     /// that contains rows for which the provided function returned false. The function
     /// is called with `KeyValuePair` containing the row key as the `Key` and `Value`
     /// gives access to the row series.
  
positive.code:     let keyNames = if keyNames = Unchecked.defaultof<_> then None else Some keyNames
      use writer = new StreamWriter(stream)
      FrameUtils.writeCsv (writer) None separator culture (Some includeRowKeys) keyNames frame
    
negative.code:   ///  * `condition` - A delegate that specifies the filtering condition.
    [<Extension>]
    static member Where(frame:Frame<'TRowKey, 'TColumnKey>, condition:Func<_, _>) = 
      frame.Rows.Where(condition) |> FrameUtils.fromRowsAndColumnKeys frame.IndexBuilder frame.VectorBuilder frame.ColumnIndex.Keys
  
    /// Filters frame rows using the specified condtion. Returns a new data frame
    /// that contains rows for which the provided function returned false. The function
  