The format code syntax {field_name:conversion}, where field_name
specifies the index number of the argument to the str.format() method
that we went through in the reordering section, and conversion
refers to the conversion code of the data type that you’re using with
the formatter.
Common String Opeerations
-------------------------
URL:
docs.python.org/3.6/library/string.html#format-specification-mini-language
Format Specification Mini-Language
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URL:
docs.python.org/3.6/library/string.html#format-specification-mini-language