# Why the following code about replace in SymPy have errors?

**URL:** https://discourse.julialang.org/t/why-the-following-code-about-replace-in-sympy-have-errors/24067
**Category:** New to Julia
**Created:** [May 10, 2019, 9:58am UTC](https://discourse.julialang.org/t/why-the-following-code-about-replace-in-sympy-have-errors/24067 "2019-05-10T09:58:55Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![gangchern](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gangchern/32/13298_2.png) [@gangchern](https://discourse.julialang.org/u/gangchern)
#### Post date: [May 10, 2019, 9:58am UTC](https://discourse.julialang.org/t/why-the-following-code-about-replace-in-sympy-have-errors/24067/1 "2019-05-10T09:58:55Z")

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### Author: ![j\_verzani](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/j_verzani/32/8551_2.png) [@j\_verzani](https://discourse.julialang.org/u/j_verzani)
#### Post date: [May 10, 2019, 4:36pm UTC](https://discourse.julialang.org/t/why-the-following-code-about-replace-in-sympy-have-errors/24067/2 "2019-05-10T16:36:15Z")

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See an answer here: [https://github.com/JuliaPy/SymPy.jl/issues/277](https://github.com/JuliaPy/SymPy.jl/issues/277) . There needs to be a lambda defined on the python side, not the julia side of things.