code: def geojson_string():
      string = """{
    "type": "FeatureCollection",
    "features": [
      {
        "type": "Feature",
        "properties": {},
        "geometry": {
          "type": "Polygon",
          "coordinates": [
            [
              [
                -66.26953125,
                -8.05922962720018
              ],
              [
                -66.26953125,
                0.7031073524364909
              ],
              [
                -57.30468749999999,
                0.7031073524364909
              ],
              [
                -57.30468749999999,
                -8.05922962720018
              ],
              [
                -66.26953125,
                -8.05922962720018
              ]
            ]
          ]
        }
      }
    ]
  }"""
      return string
  
imports: import re
  import threading
  from datetime import datetime
  from functools import reduce
  from os import environ
  from os.path import abspath, dirname, exists, isfile, join
  import pytest
  import yaml
  from pytest_socket import disable_socket
  from vcr import VCR
  import sentinelsat
  from sentinelsat import SentinelAPI, geojson_to_wkt, read_geojson
  from .custom_serializer import BinaryContentSerializer
label_desc: Use image node_id 14 for calling a global function with example usage: geojson_string() and returns: string