from typing import Dict


def _define_invertible_conditions() -> Dict[str, str]:
    """Returns a dictionary of boolean comparator strings where the value is the
    logical inverse of the key."""
    invertible_conditions = {
        ">=": "<",
        ">": "<=",
        "OR": "AND",
        "": "",
    }
    # Add reverse {value: key} entries to invertible_conditions
    reverse_inversions = {}
    for k, v in invertible_conditions.items():
        reverse_inversions[v] = k
    invertible_conditions.update(reverse_inversions)
    return invertible_conditions