[x] Replaces base Exception raises with ValueError, KeyError, BBIFileClosed or BBIReadError.
[x] Unit test refactoring
Added fixtures for bigwig and bigbed files
[x] Numpydoc-style docstrings for methods.
[x] b.chroms(chrom) will raise a KeyError instead of returning None if chrom does not exist. This seems less surprising to me. The former behavior can be achieved more explicitly with b.chroms().get(chrom).
[x] Let open support pathlib.Path objects.
[x] Make chrom and end args optional for b.values() as in records and zoom_records.
Exceptionraises withValueError,KeyError,BBIFileClosedorBBIReadError.b.chroms(chrom)will raise aKeyErrorinstead of returning None ifchromdoes not exist. This seems less surprising to me. The former behavior can be achieved more explicitly withb.chroms().get(chrom).opensupportpathlib.Pathobjects.chromandendargs optional forb.values()as inrecordsandzoom_records.