| 
  | write_xy_header(format=None,
        file=None,
        paper_size='A4',
        title=None,
        subtitle=None,
        world=None,
        view=None,
        graph_num=1,
        sets=None,
        set_names=None,
        set_colours=None,
        x_axis_type_zero=None,
        y_axis_type_zero=None,
        symbols=None,
        symbol_sizes=None,
        symbol_fill=None,
        linestyle=None,
        linetype=None,
        linewidth=None,
        data_type=None,
        seq_type=None,
        axis_labels=None,
        tick_major_spacing=None,
        tick_minor_count=None,
        legend=None,
        legend_pos=None,
        legend_box_fill_pattern=None,
        legend_char_size=None,
        norm=None) | source code |  Write the header for XY-scatter plots. Many of these keyword arguments should be supplied in a [X, Y] list 
  format, where the first element corresponds to the X data, and the second
  the Y data.  Defaults will be used for any non-supplied args (or lists 
  with elements set to None). 
    Parameters:
        format(str) - The specific backend to use.  The currently support backends are 
          'grace'.file(file object) - The file object to write the data to.paper_size(str) - The paper size, i.e. 'A4'.  For the software Grace, if not set 
          this will default to letter size.title(None or str) - The title of the graph.subtitle(None or str) - The sub-title of the graph.world(Nor or list of list of numbers) - The plot default zoom.  This consists of a list of the X-axis 
          minimum, Y-axis minimum, X-axis maximum, and Y-axis maximum 
          values.  Each graph should supply its own world view.view(None or list of float) - List of 4 coordinates defining the graph view port.graph_num(int) - The total number of graphs.sets(list of int) - The number of data sets in each graph.set_names(None or list of list of str) - The names associated with each graph data set (Gx.Sy in Grace).  
          For example this can be a list of spin identification strings.  
          The first dimension is the graph, the second is the set.set_colours(None or list of list of int) - The colours for each graph data set Gx.Sy.  The first dimension 
          is the graph, the second is the set.x_axis_type_zero(None or list of lists of bool) - The flags specifying if the X-axis should be placed at zero.y_axis_type_zero(None or list of lists of bool) - The flags specifying if the Y-axis should be placed at zero.symbols(None or list of list of int) - The symbol style for each graph data set (Gx.Sy in Grace).  The 
          first dimension is the graph, the second is the set.symbol_sizes(None or list of list of int) - The symbol size for each graph data set (Gx.Sy in Grace).  The 
          first dimension is the graph, the second is the set.symbol_fill(None or list of list of int) - The symbol file style for each graph data set (Gx.Sy in Grace).  
          The first dimension is the graph, the second is the set.linestyle(None or list of list of int) - The line style for each graph data set (Gx.Sy in Grace).  The 
          first dimension is the graph, the second is the set.linetype(None or list of list of int) - The line type for each graph data set (Gx.Sy in Grace).  The 
          first dimension is the graph, the second is the set.linewidth(None or list of float) - The line width for all elements of each graph data set (Gx.Sy in 
          Grace).  The first dimension is the graph, the second is the set.data_type(None or list of list of str) - The axis data category (in the [X, Y] list format).seq_type(None or list of list of str) - The sequence data type (in the [X, Y] list format).  This is for 
          molecular sequence specific data and can be one of 'res', 'spin',
          or 'mixed'.tick_major_spacing(None or list of list of numbers) - The spacing between major ticks.  This is in the [X, Y] list 
          format whereby the first dimension corresponds to the graph 
          number.tick_minor_count(None or list of list of int) - The number of minor ticks between the major ticks.  This is in 
          the [X, Y] list format whereby the first dimension corresponds to
          the graph number.axis_labels(None or list of list of str) - The labels for the axes (in the [X, Y] list format).  The first 
          dimension is the graph.legend(list of bool) - If True, the legend will be visible.  The first dimension is the 
          graph.legend_pos(None or list of list of float) - The position of the legend, e.g. [0.3, 0.8].  The first dimension
          is the graph.legend_box_fill_pattern(int) - The legend box fill.  If set to 0, it will become transparent.legend_char_size(float) - The size of the legend box text.norm(list of bool) - The normalisation flag which if set to True will cause all graphs
          to be normalised to 1.  The first dimension is the graph. |