pandas.Series.str.istitle
- 
Series.str.istitle()[source] - 
Check whether all characters in each string in the Series/Index are titlecase. Equivalent to
str.istitle().Returns: is : Series/array of boolean values  
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Licensed under the 3-clause BSD License.
    https://pandas.pydata.org/pandas-docs/version/0.22.0/generated/pandas.Series.str.istitle.html