I have a lot yaml file names that have similar structure but with different data. I need to parse out selective data, and put into a single csv (excel) file as three columns.

But i facing an issue with empty key, that always gives me an "KeyError: 'port'"

my yaml file example:

```
base:
   server: 10.100.80.47
   port: 3306
   namePrefix: well
   user: user1
   password: kjj&%$

 base:
   server: 10.100.80.48
   port: 
   namePrefix: done
   user: user2
   password: fhfh#$%

```

In the second block i have an empty "port", and my script is stuck on that point.
**I need that always that an empty key is found it doesn't write anything.**

```
   from asyncio.windows_events import NULL
   from queue import Empty
   import yaml
   import csv
   import glob

   yaml_file_names = glob.glob('./*.yaml')

   rows_to_write = []

   for i, each_yaml_file in enumerate(yaml_file_names):
   print("Processing file {} of {} file name: {}".format(
    i+1, len(yaml_file_names),each_yaml_file))

   with open(each_yaml_file) as file: 
    data = yaml.safe_load(file)

   for v in data:
    if "port" in v == "": 
    data['base']['port'] = ""  

  rows_to_write.append([data['base']['server'],data['base']['port'],data['server']['host'],data['server']['contex']])

  with open('output_csv_file.csv', 'w', newline='') as out:
    csv_writer = csv.writer(out)
    csv_writer.writerow(["server","port","hostname", "contextPath"])
    csv_writer.writerows(rows_to_write)
    print("Output file output_csv_file.csv created")

```