“load_embedded” loads content previously defined in the current PyMOL command script using the “embed” command.

load_embedded [ key [, name [, state [, finish [, discrete [, quiet ]]]]]]

embed wats, pdb 
HETATM    1  O   WAT     1       2.573  -1.034  -1.721 
HETATM    2  H1  WAT     1       2.493  -1.949  -1.992 
HETATM    3  H2  WAT     1       2.160  -0.537  -2.427 
HETATM    4  O   WAT     2       0.705   0.744   0.160 
HETATM    5  H1  WAT     2      -0.071   0.264   0.450 
HETATM    6  H2  WAT     2       1.356   0.064  -0.014 
embed end 

load_embedded wats 

This approach only works with text data files.

cmd.load_embedded | commands