title: subtract dataframe times get hours as floating point
body: <p>Input file &quot;clockTimes2020-40.xlsx&quot; is CSV.  Times are in columns.
  I want to calculate the time difference, &quot;dur&quot;, as number of hours in float float, but I get the error message indicated.</p>
  <pre><code>import pandas
  import datetime
  print('pandas.__version__:',pandas.__version__)
  df = pandas.read_excel('clockTimes2020-40.xlsx', sheet_name='clockTimes2020-40')
  line0 = df.loc[0]
  print('line0: ',line0)
  print('line0 type is ',type(line0))
  beg = line0[4]
  end = line0[5]
  print('beg = ',beg, 'type: ',type(beg))
  print('end = ',end, 'type: ',type(end))
  dur = end - beg
  print('dur = ',dur,'type:',type(dur))
  </code></pre>
  <p>RESULTS
  runfile('C:/Users/Muir/ABCorp/untitled0.py', wdir='C:/Users/Muir/ABCorp')
  pandas.<strong>version</strong>: 1.1.3
  line0:  CID                        1
  Lname                  Adams
  Fname              Francis J
  Mon      2020-09-28 00:00:00
  Moin                08:00:10
  Moout               17:16:24
  Tue      2020-09-29 00:00:00
  Tuin                07:58:41
  Tuout               16:55:55
  Wed      2020-09-30 00:00:00
  Wein                07:53:00
  Weout               17:45:45
  Thu      2020-10-01 00:00:00
  Thin                07:53:00
  Thout               17:45:45
  Fri      2020-10-02 00:00:00
  Frin                07:53:00
  Frout               16:59:45
  Sat      2020-10-03 00:00:00
  Sain                00:00:00
  Saout               00:00:00
  Sun      2020-10-04 00:00:00
  Suin                00:00:00
  Suout               00:00:00
  Name: 0, dtype: object
  line0 type is  &lt;class 'pandas.core.series.Series'&gt;
  beg =  08:00:10 type:  &lt;class 'datetime.time'&gt;
  end =  17:16:24 type:  &lt;class 'datetime.time'&gt;
  Traceback (most recent call last):
  File &quot;C:\Users\Muir\ABCorp\untitled0.py&quot;, line 21, in 
  dur = end - beg
  TypeError: unsupported operand type(s) for -: 'datetime.time' and 'datetime.time'</p>