How to write recipe files to a yml doc from Python using ruamel.yaml

I am trying to write a script that will take arguments and write it to a yml file so i can run a snowfakery query. Snowfakery requires the first few lines be recipe lines and the rest of the lines do not need -

- snowfakery_version: version
- object: obj
  fields:
     name: John Doe

I have tried

snowfakeryTest = {
    "- snowfakery_version": 3,
    "- object": "obj",
    "fields":{
        "name": "John doe"
    }
}

with open("simple.yml", 'w') as outfile:
    yaml_dump(snowfakeryTest, outfile,)

but the yml that is generate always looks like the image provided
enter image description here

YAML is a representation of a data structure. You need to create the appropriate data structure in memory and pass that to yaml_dump.

Your example document shows an outer data structure that's a list; it contains two dictionaries (and the second dictionary contains a nested dictionary). In Python, that would be:

snowfakeryTest = [
  {"snowfakery_version": "version"},
  {
    "object": "obj",
    "fields": {
      "name": "John Doe",
    },
  }
]

If we dump that (I'm using PyYAML instead of ruamel.yaml), we get:

- snowfakery_version: version
- fields:
    name: John Doe
  object: obj

YAML documents consist of scalars (strings of various forms, with some unquoted scalars loaded as integers,
float, booleans, datetime, etc.), mappings (normally loaded as dict in Python) and sequences (normally loaded as Python list)
Your required output consists of a root level sequence, containing (nested) mappings as elements. These elements in YAML (in block
style) are preceded by dashes (- + space), and you should not provide those yourself.

Faced with YAML output that doesn't look as required, it is often helpful to load the expected output and inspect
the resulting data structure:

import ruamel.yaml

yaml_str = """\
- snowfakery_version: version
- object: obj
  fields:
     name: John Doe
"""
    
yaml = ruamel.yaml.YAML()
data = yaml.load(yaml_str)
print(data)

which gives:

[{'snowfakery_version': 'version'}, {'object': 'obj', 'fields': {'name': 'John Doe'}}]

In this simple case you can directly copy-paste the output in your program to define the data structure, but a few
newlines and an extra comma make it more readable and extendable:

import sys
from pathlib import Path
import ruamel.yaml

snowfakeryTest = [
  {'snowfakery_version': 'version'},
  {'object': 'obj',
   'fields': {'name': 'John Doe'},
  }
]

out_file = Path('simple.yaml')

yaml = ruamel.yaml.YAML()
yaml = yaml.dump(snowfakeryTest, out_file)

print(out_file.read_text())

which gives:

- snowfakery_version: version
- object: obj
  fields:
    name: John Doe

A few notes:

• ruamel.yaml outputs to a UTF-8 stream, which is binary, so you should preferably use 'wb' to open
  the output file. Providing a pathlib.Path instance instead of a stream argument does that for you.
• The officially recommeded extension for YAML files has been .yaml since at least September 2006.
  The YML format is XML based and looks completely different
• the order of keys in the output is the same as what you specify in your Python dict. Although
  key order should be insignificant according to the YAML spec, having a predictable order can be important for
  documents stored in versioning systems.