from brian2.parsing.sympytools import expression_complexity)
Returns the complexity of an expression (either string or sympy)
The complexity is defined as 1 for each arithmetic operation except divide which is 2, and all other operations are 20. This can be overridden using the complexity argument.
Note: calling this on a statement rather than an expression is likely to lead to errors.
expr: `sympy.Expr` or str :
complexity: None or dict (optional) :
A dictionary mapping expression names to their complexity, to overwrite default behaviour.
complexity: int :
The complexity of the expression.