Getting CRS to export shapely polygon to shapefile

I am trying to export a shapely polygon to a shapefile. I have tried this, but the CRS is missing, when I try to import it in to QGIS.

The shapely polygon is from this OSMNX example but edited to work with location.

My (list of two) polygons:

In [68]:

isochrone_polys


Out[68]:
[<shapely.geometry.polygon.Polygon at 0x1d884a52cc0>,
 <shapely.geometry.polygon.Polygon at 0x1d883974f60>]

I tried this using Fiona:

from pyproj import Proj, transform
import fiona
from fiona.crs import from_epsg
Proj(isochrone_polys[0].crs)

But have an attribute error:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-100-f3e93644040a> in <module>
      2 import fiona
      3 from fiona.crs import from_epsg
----> 4 Proj(isochrone_polys[0].crs)

AttributeError: 'Polygon' object has no attribute 'crs'

The edges in and nodes in the street network in the tutorial seem to be in 4326, but when I put this in as the CRS in QGIS, it was incorrect.

edges is a geopandas dataframe, while the isochrone_polys[1] is in shapely.

type(edges)
Out[11]: geopandas.geodataframe.GeoDataFrame

type(isochrone_polys[1])
Out[12]: shapely.geometry.polygon.Polygon

print(edges.crs)
+proj=utm +zone=55 +ellps=WGS84 +datum=WGS84 +units=m +no_defs

print(isochrone_polys[1].crs)
Traceback (most recent call last):

  File "<ipython-input-16-e4c06ab91976>", line 1, in <module>
    print(isochrone_polys[1].crs)

AttributeError: 'Polygon' object has no attribute 'crs'

The polygon itself seems to be in a projected coordinate system (not sure which one):

isochrone_polys[0].bounds
Out[7]: 
(316180.5323058479,
 -4182505.539783961,
 317463.60173865134,
 -4181214.9721103134)

How would I export this properly with the correct CRS?

from osgeo import osr, ogr # import osr, ogr 
sr = osr.SpatialReference()
sr.ImportFromEPSG(4326)
driver = ogr.GetDriverByName('ESRI Shapefile')
ds = driver.CreateDataSource('abc.shp')
lyr = ds.CreateLayer('route', sr, ogr.wkbPolygon)

from osgeo import ogr, osr
from shapely.geometry import Polygon
import shapely.wkt

# read wkt and use it to create a shapely polygon P
with open('/Users/**/osmnx_test-master/isochrone_polys_0.txt') as f:
    x = f.readline()
P = shapely.wkt.loads(x)

# Now convert it to a shapefile with OGR    
sr = osr.SpatialReference()
# or sr.ImportFromProj4(edges.crs)
sr.ImportFromProj4('+proj=utm +zone=55 +ellps=WGS84 +datum=WGS84 +units=m +no_defs')
driver = ogr.GetDriverByName('ESRI Shapefile')
ds = driver.CreateDataSource('abc.shp')
layer = ds.CreateLayer('route', sr, ogr.wkbPolygon)# Add one attribute
layer.CreateField(ogr.FieldDefn('id', ogr.OFTInteger))
defn = layer.GetLayerDefn()

## If there are multiple geometries, put the "for" loop here

# Create a new feature (attribute and geometry)
feat = ogr.Feature(defn)
feat.SetField('id', 123)

# Make a geometry, from Shapely object
geom = ogr.CreateGeometryFromWkb(P.wkb)
feat.SetGeometry(geom)
layer.CreateFeature(feat)
feat =  None 

# Save and close the data source
ds = None