How do I convert a bone to b-bone with Python and set the number of segments I made a string of bones but want specific bones to be b-bones
I have:
bpy.ops.object.armature_add()

the python suggestion is:
bpy.data.armatures['Armature'].draw_type

how do I define b-bone from this?
You cannot have specific bones as b-bones..it's all of them or none of them - the type is for the whole armature. You can have all as b-bones and set the segments to more than 1 only for the specific ones.

import bpy

bpy.data.armatures['Armature'].draw_type = 'BBONE'

bpy.data.armatures['Armature'].bones['Bone'].bbone_segments = 3