Two questions need some help

Questions
1

Hello, I am a new one, and I have twe questions here.

1.how to use pm.traceplot to show a specific parameter

My model like this,

with pm.Model() as basic_model1:

    # Priors for unknown model parameters
    beta = pm.Uniform('beta', lower=uniMin, upper=uniMax, shape=varNum)
    #beta = pm.TruncatedNormal('beta', sigma=10, lower=uniMin, upper=uniMax, shape=varNum)
    sigma = pm.HalfNormal('sigma', sigma=1)

   # Expected value of outcome
    mu, observedYGpp = CallOutFunc(beta)
    #print(mu)

    # Likelihood (sampling distribution) of observations
    Y_obs = pm.Normal('Y_obs', mu=mu, sigma=sigma, observed=observedYGpp)

The pm.summary showed

mean sd mc_error hpd_2.5 hpd_97.5 n_eff Rhat
beta__0 0.249684 0.028431 0.000368 0.205333 0.299698 4806.975880 0.999800
beta__1 1.526045 0.292212 0.004429 1.049262 1.999820 4430.624578 0.999889
beta__2 31.930996 7.191544 0.123749 20.280235 43.499886 4012.944395 0.999818
beta__3 75.259162 10.943734 0.159996 57.341661 92.985441 3723.871450 0.999947
beta__4 52.268268 5.396875 0.094701 43.302025 61.097688 3756.195182 0.999831
beta__5 0.324796 0.039853 0.000645 0.259021 0.390000 4107.612072 1.000899
beta__6 0.553403 0.028949 0.000455 0.506692 0.599996 3615.974080 0.999845
beta__7 19.998619 7.458532 0.114492 7.725570 31.940577 3752.045594 1.000350
beta__8 0.102020 0.030513 0.000500 0.051829 0.149996 3570.146106 0.999811
sigma 19.425252 18.630350 1.862747 0.797885 38.663130 1.000374 79.013995

I can use pm.traceplot(trace, var_names=['beta']) to draw all the betas, but the screen is too small to show it well. Hence, I would like to know how I can draw one of beta on one picture? e.g. pm.traceplot(trace, var_names=['beta__0 ']) .

2.How to change target_accept
I used trace = pm.sample(epohs, cores=1, tune=3000) to run the model, but it indicated me to modify the targetaccept Increase `target_accept` or reparameterize.
I try add the target_accept, but it failed.

3.I installed the pymc3 by using the following command last week, so it should be the newest version.
pip install git+https://github.com/pymc-devs/pymc3

Thanks