title: Python split string based on conditional
body: <p>I want to split strings using a comma delimiter if the comma is preceded by a certain regex. Consider the case where my strings are in the format:
  "(bunch of stuff that might have commas) FOO_REGEX, (other stuff that might have commas) FOO_REGEX, ..." and I want to split the string on commas, but only if they're preceded by FOO_REGEX: ["(bunch of stuff that might have commas) FOO_REGEX", "(other stuff that might have commas) FOO_REGEX", tc.].</p>
  
  <p>As a concrete example, consider splitting the following string: </p>
  
  <pre><code>"hi, hello! $$asdf, I am foo, bar $$jkl, cool" 
  </code></pre>
  
  <p>into this list of three strings:</p>
  
  <pre><code>["hi, hello! $$asdf", 
  "I am foo, bar $$jkl", 
  "cool"]
  </code></pre>
  
  <p>Is there any easy way to do this in python?</p>