The trait for types that can be created from strings
FromStr - A trait to abstract the idea of creating a new instance of a type from a string.FromStrA trait to abstract the idea of creating a new instance of a type from a string.
from_strfn from_str(s: &str) -> Option<Self>Parses a string s to return an optional value of this type. If the string is ill-formatted, the None is returned.