Fat graphs behave badly when not connected

[videlec]

from surface_dynamics import FatGraph
fg = FatGraph('(0,1)(2,3)', '(0,1)(2,3)')
fg.genus()

gives -1 (but it is two genus 0 components)

[fchapoton]

so this should be closed now ?

[saraedum]

I guess, but the example actually gives product is not identity now @videlec .

[videlec]

The input format has changed as well as the output of fg.genus()

sage: fg = FatGraph('(0,1)(2,3)')
sage: fg.genus()
0
sage: fg.is_connected()
False

It is not clear to me whether genus() would better raise an error for disconnected surface.