Getting "|as_crispy_field got passed an invalid or inexistent field" with a field that exists - html

Question

I'm using django-crispy-forms, and have run across an issue where one of my form fields won't render. The error I'm getting is telling me that the form field is either inexistent or invalid, but it definitely exists, and it's pretty much copied from other form fields that work properly on other pages. So I don't really see how it is either of those.
Here's the relevant code:
forms.py
class AddSkillsForm:
all_skills = forms.CharField(
label="Skills ",
widget=forms.HiddenInput(),
required=False
)
view.html
{% extends 'base.html' %}
{% load crispy_forms_tags %}
{% block title %}{{ course.name }}{% endblock %}
{% block content %}
{% include 'course/partial/nav.html' with course=course active_breadcrumb=None %}
<div class="card">
<div class="card-header">
{% include 'course/partial/menu.html' with course=course %}
</div>
<div class="card-body">
<dl class="row">
<dt class="col-sm-3">Name:</dt>
<dd class="col-sm-9">{{ course.name }}</dd>
<dt class="col-sm-3">Number of Students:</dt>
<dd class="col-sm-9">{{ total_students }}</dd>
<dt class="col-sm-3">Sections:</dt>
<dd class="col-sm-9">
{% for section in sections %}
<p>{{ section.name }}</p>
{% endfor %}
</dd>
</dl>
</div>
<div class="card-body">
<p>First, you'll need to import any existing students and groups from Canvas</p>
<a class="btn btn-primary" href="{% url 'import_students_and_groups' course.id%}">
Import Students and Groups from Canvas
</a>
<div id="skill_box">
<p>If you would like to use self-reported student skills to form teams, you can define the skills relevant to this course here</p>
<div id="skill_container"></div>
<button type="button" class="btn btn-primary">Add Skill</button>
<form method="post">
{% csrf_token %}
{{ form.all_skills|as_crispy_field }}
<button type="submit" class="btn btn-primary"></button>
</form>
</div>
</div>
</div>
{% endblock %}

Answer 1

In case anyone comes across the same issue, I did find the solution.
In forms.py, each form must take forms.Form as a parameter in order to function properly with django-crispy-forms. I had a different form that I wasn't accessing regularly that also did not do this, so I didn't realize that all the functional forms did. Here's the revised code
forms.py
class AddSkillsForm:
all_skills = forms.CharField(
label="Skills ",
widget=forms.HiddenInput(),
required=False
)