IndexOut_of_Range

Error in gen_structure: IndexError: list index out of range

When running gen_structure against a gromacs topology file, user may encounter an error message of

IndexError: list index out of range

In this case, user is first advised to see the square bracket in the topology file.
If user's bracket is something like [molecules... (no space after "[") or does not have any space within [...],
the error message will appear.
gen_structure may then work simply by adding a space after "[" or by adding a space anywhere within [...]