code: def _f90str(self, value):
          
          # Replace Python quote escape sequence with Fortran
          result = repr(str(value)).replace("\\'", "''").replace('\\"', '""')
  
          # Un-escape the Python backslash escape sequence
          result = result.replace('\\\\', '\\')
  
          return result
docs: Return a Fortran 90 representation of a string.