pos: where to add the new element relative to the cursor, one of after", "before", "on".
header: display header if TRUE
alignment: columns alignement, argument length must match with columns length, values must be "l" (left), "r" (right) or "c" (center).
align_table: table alignment within document, value must be "left", "center" or "right"
stylenames: columns styles defined by table_stylenames()
first_row: Specifies that the first column conditional formatting should be applied. Details for this and other conditional formatting options can be found at http://officeopenxml.com/WPtblLook.php.
first_column: Specifies that the first column conditional formatting should be applied.
last_row: Specifies that the first column conditional formatting should be applied.
last_column: Specifies that the first column conditional formatting should be applied.
no_hband: Specifies that the first column conditional formatting should be applied.
no_vband: Specifies that the first column conditional formatting should be applied.