Regarding concatenation of a list to a string

[Kedar]

This is the code I wrote initially,

print("Once upon a time, 5 men were walking by the forest")
warriors = ["Kevin", "Casper", "Nick", "Jim", "Napolean"]
print("The names of these men were: " + (warriors))

However, it gives TypeError : can only concatenate str (not "list") to str

So I modified the code this way:

print("Once upon a time, 5 men were walking by the forest")
warriors = ["Kevin", "Casper", "Nick", "Jim", "Napolean"]
print("The names of these men were: " + str(warriors))

And now its working fine, but I don't understand why

It would be great if you could explain this to me.

Thanks