code: def multi_point(point_gdf):
      """Create a multi-point GeoDataFrame."""
      multi_point = point_gdf.union_all()
      out_df = GeoDataFrame(
          geometry=GeoSeries(
              [
                  multi_point,
                  Point(2, 5),
                  Point(-11, -14),
                  Point(-10, -12),
              ]
          ),
          crs="EPSG:3857",
      )
      out_df["attr"] = ["tree", "another tree", "shrub", "berries"]
      return out_df
  
imports: import numpy
  import shapely
  from shapely.geometry import Polygon, Point, LineString, LinearRing, GeometryCollection, MultiPoint, box
  import geopandas
  from geopandas import GeoDataFrame, GeoSeries, clip
  from geopandas.testing import assert_geodataframe_equal, assert_geoseries_equal
  import pytest
  from geopandas.tools.clip import _mask_is_list_like_rectangle
label_desc: Use image node_id 15 for calling a global function with example usage: multi_point(point_gdf) and returns: out_df