Fix: raise TypeError instead of return TypeError

[smsharma]

The Bug

File: linx/reactions.py, line 161

else:
    return TypeError('Must include spline data points or analytic...')

This returns a TypeError instance instead of raising it.

Impact

When a Reaction is created without providing either spline_data or frwrd_rate_param_func:

1. __init__ returns a TypeError object (which is truthy, not an error)
2. Object construction appears to "succeed"
3. The reaction object is in an invalid state (missing required data)
4. Causes cryptic failures later when the object is actually used

Example of the problem

# This SHOULD fail but doesn't:
rxn = Reaction(name="bad", in_states=(...), out_states=(...), 
               alpha=1, beta=2, gamma=3)
# rxn is now a TypeError instance, not a Reaction!

# Later code fails mysteriously:
rxn.frwrd_rate_param(T, p)  # AttributeError: 'TypeError' has no attribute...

The Fix

Change return TypeError(...) → raise TypeError(...)

🤖 Generated with Claude Code

[cgiovanetti]

Thanks, good catch!