how to select in secuence

is there any way to actually make the python script to select one face after the other?
for now i was using “select all” but after i make a bisect on it , all of it deselects, besides i do not necesarily need to make the cut (and can just select the one i want better).

for that i need a way to unselect and select a part of what i need using just
bpy.ops.mesh will be even better thanks

hope someone knows