Importing the C API fails on Windows

I am trying to build a C++ Python extension (with pybind11) that uses MPI and mpi4py on Windows. I am working in a conda environment and I installed mpi4py as follows:

conda install mpi4py -c conda-forge --yes

The following:

// import the mpi4py API
if (import_mpi4py() < 0) {
  throw std::runtime_error("Could not load mpi4py API.");
}

throws the exception. Running mpiexec -n 4 python -c “from mpi4py import MPI; comm = MPI.COMM_WORLD; print(comm.Get_rank())” works as expected. I am not sure whether this is a bug or some silly mistake I am making.

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