When I do dissolve:

With this specific shapefile happens with other similar it is working fine.
Also I checked for null values in the geometry and there weren't any.

```
data2 = pst[pst['PROP_TYPE'].str.startswith(('01'))]
dslvd=data2.dissolve(by='PROP_TYPE')

TopologyException: Input geom 1 is invalid: Ring Self-intersection at or near point 223630.72975008655 4405823.482638143 at 223630.72975008655 4405823.482638143
TopologyException: Input geom 1 is invalid: Ring Self-intersection at or near point 223630.72975008655 4405823.482638143 at 223630.72975008655 4405823.482638143
TopologyException: Input geom 1 is invalid: Ring Self-intersection at or near point 223630.72975008655 4405823.482638143 at 223630.72975008655 4405823.482638143

 No Shapely geometry can be created from null value

During handling of the above exception, another exception occurred:

```

What could be wrong?