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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 Phenotype Phase Plane
Phenotype phase planes will show distinct phases of optimal growth with different use of two different substrates. For more information, see Edwards et al.
Cobrapy supports calculating and plotting (using matplotlib) these phenotype phase planes. Here, we will make one for the "textbook" E. coli core model.
Step1:  We want to make a phenotype phase plane to evaluate uptakes of Glucose and Oxygen.
Step2:  If brewer2mpl is installed, other color schemes can be used as well
Step3:  The number of points which are plotted in each dimension can also be changed
Step4:  The code can also use multiple processes to speed up calculations
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Python Code:
%matplotlib inline
from time import time
import cobra.test
from cobra.flux_analysis import calculate_phenotype_phase_plane
model = cobra.test.create_test_model("textbook")
Explanation: Phenotype Phase Plane
Phenotype phase planes will show distinct phases of optimal growth with different use of two different substrates. For more information, see Edwards et al.
Cobrapy supports calculating and plotting (using matplotlib) these phenotype phase planes. Here, we will make one for the "textbook" E. coli core model.
End of explanation
data = calculate_phenotype_phase_plane(model, "EX_glc__D_e", "EX_o2_e")
data.plot_matplotlib();
Explanation: We want to make a phenotype phase plane to evaluate uptakes of Glucose and Oxygen.
End of explanation
data.plot_matplotlib("Pastel1")
data.plot_matplotlib("Dark2");
Explanation: If brewer2mpl is installed, other color schemes can be used as well
End of explanation
calculate_phenotype_phase_plane(model, "EX_glc__D_e", "EX_o2_e",
                                reaction1_npoints=20,
                                reaction2_npoints=20).plot_matplotlib();
Explanation: The number of points which are plotted in each dimension can also be changed
End of explanation
start_time = time()
calculate_phenotype_phase_plane(model, "EX_glc__D_e", "EX_o2_e", n_processes=1,
                                reaction1_npoints=100, reaction2_npoints=100)
print("took %.2f seconds with 1 process" % (time() - start_time))
start_time = time()
calculate_phenotype_phase_plane(model, "EX_glc__D_e", "EX_o2_e", n_processes=4,
                                reaction1_npoints=100, reaction2_npoints=100)
print("took %.2f seconds with 4 process" % (time() - start_time))
Explanation: The code can also use multiple processes to speed up calculations
End of explanation
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