import math


def _deg2rad(coords_dict):
    """
    Take a dictionary with microphone array
    capsules and 3D polar coordinates to
    convert them from degrees to radians

    colatitude, azimuth, and radius (radius
    is left intact)
    """
    return {
        m: [math.radians(c[0]), math.radians(c[1]), c[2]]
        for m, c in coords_dict.items()
    }