Django admin.display colored_name in html

How can you add an html in django admin display?

from django.contrib import admin
from django.db import models
from django.utils.html import format_html

class Person(models.Model):
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)
    color_code = models.CharField(max_length=6)

    @admin.display
    def colored_name(self):
        return format_html(
            '<span style="color: #{};">{} {}</span>',
            self.color_code,
            self.first_name,
            self.last_name,
        )

class PersonAdmin(admin.ModelAdmin):
    list_display = ('first_name', 'last_name', 'colored_name')

Test case in accounting. I need something like this to downlaod invoices from admin list view. 

 def docs_current(self, obj: Transaction) -> str: # Show files
        docs = Document.objects.filter(transaction=obj)
        urls = ""
        for doc in docs:
            urls = urls + doc.invoice.url
        return urls 

Admin example to display urls.  

class TransactionAdmin(admin.ModelAdmin):
    actions = [expenses, sales, waiting, internal]
    search_fields = ('name', 'explanation', )
    list_filter = ('transaction_type', 'paymentmethod', 'accounting_period__full_name', 'transaction_date', DocsCountFilter)
    list_display = ('name', 'explanation', 'transaction_date', 'docs_count', 'docs_current')
    inlines = [
        DocumentInline,
    ]

    def docs_count_current(self, obj: Transaction) -> str: # Only used to test count sync denormalisated
        return str(Document.objects.filter(transaction=obj).count())

    @admin.display
    def docs_current(self, obj: Transaction) -> str:
        docs = Document.objects.filter(transaction=obj)
        urls = ""
        for doc in docs:
            urls = urls + doc.invoice.url + "<br />"
        return format_html(urls)