As others have posted, the regular expression you are looking for is:
\d{4}-\d{6}
The full code I would use:
import re
my_string = 'Ticketing TSX - 2016-049172'
matches = re.findall(r"\d{4}-\d{6}", my_string)
print matches
If, for example, the length of the second digit varies from 6 to 8 digits, you will need to update your regular expression to this.
\d{4}-\d{6,8}
All of the details about regex and using regex in Python is available in the docs
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