[Feature] Equality of metabolites and reactions

[oxinabox]

Checklist

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Problem

I want to be able to detect if metabolites or reactions are equal so i can avoid adding duplicates to my model.

Consider:

In [1]: from cobra import Model, Reaction, Metabolite

In [2]: m_o2 = Metabolite("o2", "O2", "oxygen")

In [3]: m_o2 == m_o2.copy()
Out[3]: False

In [4]:     ex_o2 = Reaction("EX_o2", lower_bound=-100, upper_bound=100)
    ...:     ex_o2.add_metabolites({m_o2: -1})
    ...: 

In [5]: ex_o2 == ex_o2.copy()
Out[5]: False

Solution

The exact details of how this would work is unclear to me.
In terms of should it require that the metabolites have same id, or should it require a deeper check that they are equal in all fields.
Should it allow different id if name is the same?

In general though we should be be able to detect if reactions are the same.

Alternatives

In general it seems like sometimes reactions are considered equal if they have the same identifier.
Except the equality operator is not implemented.
E.g. model.add_reactions will ignore requests to add things with same id

In [29]: model.add_reactions([ex_o2])

In [30]: model.add_reactions([ex_o2])
Ignoring reaction 'EX_o2' since it already exists.

Anything else?

No response