File Name issue

[Steve]

The line:
with open("HOURLYLOG.txt", 'r') as infile:
works but, when I rename the file, the line:
with open("HOURLY-LOG.txt", 'r') as infile:
does not.  The complaint is: Cannot Assign to operator

However, I have:
BPM_O2s=open("BPM-O2-Readings.txt","a")
And it works.

At first, I thought the issue was due to having the - in the filename.

Is there a fix or explanation for this?
Steve




FootNote:
Would it be ironic if Popeye's chicken was fried in Olive Oil?