New function for interim fields formatting

[xispa]

Description of the issue/feature this PR addresses

This Pull Request adds a function to make the formatting of interim fields easier. It also adds a new function to_list in the api

Current behavior before PR

Formatting values and units of interim fields for human visualization is cumbersome

Desired behavior after PR is merged

Formatting values and units of interim fields for human visualization made easy

--
I confirm I have tested this PR thoroughly and coded it according to PEP8
and Plone's Python styleguide standards.

[ramonski]

Please split this function into 2, e.g. something like this:

def parse_json(thing, default=""):
    """Parse from JSON
    """
    try:
        return json.loads(thing)
    except (TypeError, ValueError):
        return default

def to_list(value):
    """Converts the value to a list
    :param value: the value to be represented as a list
    :returns: a list that represents or contains the value
    """
    if is_string(value):
        value = parse_json(value, [])
    if not isinstance(value, (list, tuple, set)):
        value = [value]
    return list(value)

[xispa]

Done with 4134d9b

[ramonski]

Only a minor thing to increase reusability

[grulisco]

❤️