<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def unit_key_from_name(name):
 """Return a legal python name for the given name for use as a unit key."""

  result = name

  for old, new in six.iteritems(UNIT_KEY_REPLACEMENTS):
    result = result.replace(old, new)

  # Collapse redundant underscores and convert to uppercase.
  result = re.sub(r'_+', '_', result.upper())

  return result