PyQGIS doesn't load user libraries properly

I’m trying to put my PyQGIS functions in separate .py files and load them from my main script.

from qgis.core import QgsProject

def getVectorLayerGeo():
    
    project = QgsProject.instance()
    layers = project.mapLayersByName('Yalcowinna')
    layer = layers[0]
    features=layer.getFeatures()

    coords = list()
    
    for feature in features:
        geom = feature.geometry()
        geomSingleType = QgsWkbTypes.isSingleType(geom.wkbType())
        if geom.type() == QgsWkbTypes.PointGeometry:
            if geomSingleType:
                x = geom.asPoint()
                print("Point: ", x)
            else:
                x = geom.asMultiPoint()
                print("MultiPoint: ", x)
        elif geom.type() == QgsWkbTypes.PolygonGeometry:
            if geomSingleType:
                x = geom.asPolygon()
                print("Polygon: ", x, "Area: ", geom.area())
            else:
                x = geom.asMultiPolygon()
                print("MultiPolygon: ", x, "Area: ", geom.area())
        else:
            print("Unknown or invalid geometry")

    for coord in x[0][0]:
        coords.append([coord.x(),coord.y()])
        
    return coords
    
print(getVectorLayerGeo())

does exactly what it’s supposed to, which is print a list of coordinates (as lists).

Then I try to call getVectorLayerGeo from another script:

import ee
from ee_plugin import Map
from qgis.core import QgsProject
from get_layer_coords import getVectorLayerGeo

vizParams = {'bands' : ['B4', 'B3', 'B2'], 'min':0, 'max':10000}
geom = ee.Geometry.Polygon(getVectorLayerGeom())
S2 = ee.ImageCollection("COPERNICUS/S2_SR")
image = S2.filterBounds(geo).first()

Map.addLayer(image, vizParams, 'Sentinel-2')
Map.centerObject(image, 10)

and I get

Traceback (most recent call last):
  File "C:PROGRA~1QGIS 3.16appsPython37libcode.py", line 90, in runcode
    exec(code, self.locals)
  File "<input>", line 1, in <module>
  File "<string>", line 4, in <module>
  File "C:/PROGRA~1/QGIS 3.16/apps/qgis/./pythonqgisutils.py", line 792, in _import
    mod = _builtin_import(name, globals, locals, fromlist, level)
  File "C:/Users/Glen Shennan/Google Drive/African Lovegrass/ShannFlatget_layer_coords.py", line 56, in <module>
    print(getVectorLayerGeo())
  File "C:/Users/Glen Shennan/Google Drive/African Lovegrass/ShannFlatget_layer_coords.py", line 18, in getVectorLayerGeo
    geomSingleType = QgsWkbTypes.isSingleType(geom.wkbType())
NameError: name 'QgsWkbTypes' is not defined

The thing is, when I copy getVectorLayerGeo into my main script it works as intended. Obviously I have the solution for this case but I’m intending to write a lot of functions and I don’t want to put them all in one giant script.

QgsWkbTypes is part of qgis.core, but when I import qgis.core at the start of get_layer_coords.py script it doesn’t seem to help. Am I doing something wrong or does QGIS not like calling functions from other .py files?

from qgis.core import QgsProject, QgsWkbTypes