def generate_fa_sizes(fname, outname):
"""Generate a fa.sizes file.
Parameters
----------
fname : str
Filename of input FASTA file.
outname : str
Filename of output BED file.
"""
f = Fasta(fname)
with open(outname, "w") as sizes:
for seqname, seq in f.items():
sizes.write(f"{seqname}\t{len(seq)}\n")
