<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def validate(self, fixerrors=True):
 """ Validates that the geometry is correctly formatted according to the geometry type. Parameters: - **fixerrors** (optional):
 Attempts to fix minor errors without raising exceptions (defaults to True) Returns: - True if the geometry is valid. Raises: - An Exception if not valid. """


        # validate nullgeometry or has type and coordinates keys
        if not self._data:
            # null geometry, no further checking needed
            return True
        elif "type" not in self._data or "coordinates" not in self._data:
            raise Exception("A geometry dictionary or instance must have the type and coordinates entries")
        
        # first validate geometry type
        if not self.type in ("Point","MultiPoint","LineString","MultiLineString","Polygon","MultiPolygon"):
            if fixerrors:
                coretype = self.type.lower().replace("multi","")
                if coretype == "point":
                    newtype = "Point"
                elif coretype == "linestring":
                    newtype = "LineString"
                elif coretype == "polygon":
                    newtype = "Polygon"
                else:
                    raise Exception('Invalid geometry type. Must be one of: "Point","MultiPoint","LineString","MultiLineString","Polygon","MultiPolygon"')
                
                if self.type.lower().startswith("multi"):
                    newtype = "Multi" + newtype
                    
                self.type = newtype
            else:
                raise Exception('Invalid geometry type. Must be one of: "Point","MultiPoint","LineString","MultiLineString","Polygon","MultiPolygon"')

        # then validate coordinate data type
        coords = self._data["coordinates"]
        if not isinstance(coords, (list,tuple)): raise Exception("Coordinates must be a list or tuple type")

        # then validate coordinate structures
        if self.type == "Point":
            if not len(coords) == 2: raise Exception("Point must be one coordinate pair")
        elif self.type in ("MultiPoint","LineString"):
            if not len(coords) > 1: raise Exception("MultiPoint and LineString must have more than one coordinates")
        elif self.type == "MultiLineString":
            for line in coords:
                if not len(line) > 1: raise Exception("All LineStrings in a MultiLineString must have more than one coordinate")
        elif self.type == "Polygon":
            for exterior_or_holes in coords:
                if not len(exterior_or_holes) >= 3: raise Exception("The exterior and all holes in a Polygon must have at least 3 coordinates")
        elif self.type == "MultiPolygon":
            for eachmulti in coords:
                for exterior_or_holes in eachmulti:
                    if not len(exterior_or_holes) >= 3: raise Exception("The exterior and all holes in all Polygons of a MultiPolygon must have at least 3 coordinates")

        # validation successful
        return True