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()