How to get the classes to be called by other addons?

Question

if I want these classes to be called by other plugins, like Pie Menu Editor addon, What code should I add？

import bpy
class Cam_Base(bpy.types.Operator):
    bl_idname = "cam.base"
    bl_label = "Cam Base"
    cam_name = "C_"
def execute(self, context):
    C = bpy.context

    # lock cam
    bpy.context.object.lock_scale = (True, True, True)
    bpy.context.object.lock_rotation = (True, True, True)
    bpy.context.object.lock_location = (True, True, True)

    # select cam
    bpy.context.space_data.camera = bpy.data.objects[self.cam_name]

    # Select Active Cam
    for area in C.screen.areas:
        if area.type == 'VIEW_3D':
            A = C.area.spaces.active.camera

    bpy.context.scene.camera = bpy.data.objects[A.name]

    bpy.context.space_data.shading.color_type = 'OBJECT'
    bpy.context.space_data.region_3d.view_perspective = 'CAMERA'

#############Supplementary Code################
        #Modify camera attributes
        bpy.data.objects[A.name].lock_scale[0] = True
        bpy.data.objects[A.name].lock_scale[1] = True
        bpy.data.objects[A.name].lock_scale[2] = True
        bpy.data.objects[A.name].lock_location[0] = True
        bpy.data.objects[A.name].lock_location[1] = True
        bpy.data.objects[A.name].lock_location[2] = True
        bpy.data.objects[A.name].lock_rotation[0] = True
        bpy.data.objects[A.name].lock_rotation[1] = True
        bpy.data.objects[A.name].lock_rotation[2] = True
        bpy.data.objects[A.name].scale[0] = 1
        bpy.data.objects[A.name].scale[1] = 1
        bpy.data.objects[A.name].scale[2] = 1
        bpy.data.cameras[A.name].display_size = 0.05
        bpy.data.cameras[A.name].background_images[0].alpha = 0
        bpy.data.cameras[A.name].dof.use_dof = False
        bpy.data.cameras[A.name].clip_start = 25
        bpy.data.cameras[A.name].clip_end = 100000
        bpy.data.cameras[A.name].background_images[0].scale = 1
        bpy.data.cameras[A.name].background_images[1].scale = 1
        bpy.data.cameras[A.name].background_images[2].scale = 1
    bpy.ops.view3d.view_center_camera()
    bpy.ops.image.reload()

    #select camera as active objcet in object mode
    if bpy.context.object.mode == 'OBJECT':
        bpy.ops.object.select_all(action='DESELECT')
        objectToSelect = bpy.data.objects[A.name]
        objectToSelect.select_set(True)
        bpy.context.view_layer.objects.active = objectToSelect

#############Supplementary Code################
        return {'FINISHED'}
class Cam_0V0(Cam_Base):
    bl_idname = "cam.0v0"
    bl_label = "Cam_0V0"
    cam_name = "C_0V0"
class Cam_0V1(Cam_Base):
    bl_idname = "cam.0v1"
    bl_label = "Cam_0V1"
    cam_name = "C_0V1"
class Cam_0V2(Cam_Base):
    bl_idname = "cam.0v2"
    bl_label = "Cam_0V2"
    cam_name = "C_0V2"
addon_keymaps = []
def register():
    bpy.utils.register_class(Cam_Base)
    bpy.utils.register_class(Cam_0V0)
    bpy.utils.register_class(Cam_0V1)
    bpy.utils.register_class(Cam_0V2)
def unregister():
    bpy.utils.unregister_class(Cam_Base)
    bpy.utils.unregister_class(Cam_0V0)
    bpy.utils.unregister_class(Cam_0V1)
    bpy.utils.unregister_class(Cam_0V2)
if name == "main":
    register()

Answer 1

You need to use context overrides. In this example, I added your operator buttons into the header of the Python Console:

import bpy
class Cam_Base():
    bl_idname = "cam.base"
    bl_label = "Cam Base"
    cam_name = "C_"
def execute(self, context):
    area_type = 'VIEW_3D'
    areas = [area for area in bpy.context.window.screen.areas if area.type == area_type]

    if len(areas) <= 0:
        raise Exception(f"Make sure an Area of type {area_type} is open or visible in your screen!")

    with bpy.context.temp_override(area=areas[0]):        
        c = bpy.context
        c.object.lock_scale = (True, True, True)
        c.object.lock_rotation = (True, True, True)
        c.object.lock_location = (True, True, True)
        c.space_data.camera = bpy.data.objects[self.cam_name]
        c.scene.camera = bpy.data.objects[self.cam_name]

    return {'FINISHED'}



class Cam_0V0(bpy.types.Operator, Cam_Base):
    bl_idname = "cam.cam0"
    bl_label = "Cam_0V0"
    cam_name = "C_0V0"
class Cam_0V1(bpy.types.Operator, Cam_Base):
    bl_idname = "cam.cam1"
    bl_label = "Cam_0V1"
    cam_name = "C_0V1"
class Cam_0V2(bpy.types.Operator, Cam_Base):
    bl_idname = "cam.cam2"
    bl_label = "Cam_0V2"
    cam_name = "C_0V2"
class Info_Head(bpy.types.Header):
    bl_space_type = 'INFO'
def draw(self, context):
    self.layout.operator("cam.cam0")
    self.layout.operator("cam.cam1")
    self.layout.operator("cam.cam2")

bpy.types.CONSOLE_HT_header.prepend(draw)



addon_keymaps = []
def register():
    bpy.utils.register_class(Cam_0V0)
    bpy.utils.register_class(Cam_0V1)
    bpy.utils.register_class(Cam_0V2)
def unregister():
    bpy.utils.unregister_class(Cam_0V0)
    bpy.utils.unregister_class(Cam_0V1)
    bpy.utils.unregister_class(Cam_0V2)
if name == "main":
    register()