default checkbox with vuetify

I want to set the first checkbox as checked by default, but it's not working. I'm using the option 'value=true', and I also tried with 'v-model=true', but it still doesn't work. Here's the code snippet:

with vuetify.VCard(classes="mb-2"):
            with vuetify.VCardTitle():
                vuetify.VSubheader("Materiaux :", dense=True)
            with vuetify.VCardText():
                with vuetify.VRow():
                    with vuetify.VCol(cols="auto"):
                        vuetify.VCheckbox(label="1", dense=True, value=True)
                    vuetify.VDivider(vertical=True, classes="mx-1")
                    with vuetify.VCol(cols="auto"):
                        vuetify.VCheckbox(label="2", dense=True)
                    vuetify.VDivider(vertical=True, classes="mx-1")
                    with vuetify.VCol(cols="auto"):
                        vuetify.VCheckbox(label="3", dense=True)
                    vuetify.VDivider(vertical=True, classes="mx-1")
                    with vuetify.VCol(cols="auto"):
                        vuetify.VCheckbox(label="4", dense=True)