dict_utils.py

def dict_merge(main, default, c_path=[]):
    """
    Pure dict deep-merge function. First dict has precedence.
    """
    if isinstance(main, dict):
        if default and not isinstance(default, dict):
            print(str(c_path))
            raise ValueError('Skew-level dictionaries cannot be merged at %s' % ('.'.join(c_path)))
        return {
            k: dict_merge(
                main[k],
                default=({} if default is None else default).get(k),
                c_path=c_path + [(k if isinstance(k, str) else '[%i]' % k)]
            ) if k in main else default[k]
            for k in ({} if default is None else default.keys()) | main.keys()
        }
    else:
        return main


def dict_prune_nulls(tree):
    """
    Prune None values out of dictionaries.
    Empty maps as well go away.
    """
    if isinstance(tree, dict):
        pruned = {
            k: v
            for k, v in {
                k2: dict_prune_nulls(v2)
                for k2, v2 in tree.items()
            }.items()
            if v is not None
        }
        if pruned:
            return pruned
        else:
            return None
    elif isinstance(tree, list):
        return [
            v
            for v in (
                dict_prune_nulls(v2)
                for v2 in tree
            )
            if v is not None
        ]
    else:
        return tree