str.isnumeric
method to check if all characters are numericReturns true
for all non-empty strings that only contain numeric characters.
```In [1]: 'a'.isnumeric() Out[1]: False
In [2]: ''.isnumeric() Out[2]: False
In [3]: '1'.isnumeric() Out[3]: True
In [4]: '123'.isnumeric() Out[4]: True ```