def font(row, col, sheet = nil)
      sheet ||= default_sheet
      read_cells(sheet)
      row, col   = normalize(row, col)
      style_name = @style[sheet][[row, col]] || @style_defaults[sheet][col - 1] || 'Default'
      @font_style_definitions[style_name]
    end
def font(row, col, sheet = nil)
      sheet ||= default_sheet
      read_cells(sheet)
      row, col   = normalize(row, col)
      style_name = @style[sheet][[row, col]] || @style_defaults[sheet][col - 1] || 'Default'
      @font_style_definitions[style_name]
    end
Given a cell, return the cell's style