We've now shown you two ways to specify the source for a program, one with a list of files:
Program('hello', ['file1.c', 'file2.c'])
And one with a single file:
You could actually put a single file name in a list, too, which you might prefer just for the sake of consistency:
SCons functions will accept a single file name in either form. In fact, internally, SCons treats all input as lists of files, but allows you to omit the square brackets to cut down a little on the typing when there's only a single file name.
Although SCons functions are forgiving about whether or not you use a string vs. a list for a single file name, Python itself is more strict about treating lists and strings differently. So where SCons allows either a string or list:
Trying to do "Python things" that mix strings and lists will cause errors or lead to incorrect results: