ALMA “Frequency Support” strings have the form:
[100.63..101.57GHz,488.28kHz, XX YY] U [102.43..103.37GHz,488.28kHz, XX YY] U [112.74..113.68GHz,488.28kHz, XX YY] U [114.45..115.38GHz,488.28kHz, XX YY]
at least, as far as we have seen. The “U” is meant to be the Union symbol. This function will parse such a string into a list of pairs of astropy Quantities representing the frequency range. It will ignore the resolution and polarizations.