code: def _f90repr(self, value):
          
          if isinstance(value, bool):
              return self._f90bool(value)
          elif isinstance(value, numbers.Integral):
              return self._f90int(value)
          elif isinstance(value, numbers.Real):
              return self._f90float(value)
          elif isinstance(value, numbers.Complex):
              return self._f90complex(value)
          elif isinstance(value, basestring):
              return self._f90str(value)
          elif value is None:
              return ''
          else:
              raise ValueError('Type {0} of {1} cannot be converted to a Fortran'
                               ' type.'.format(type(value), value))
docs: Convert primitive Python types to equivalent Fortran strings.