# gmsh_api package with some useful classes 
import gmsh_api
# original gmsh-api from gmsh package
import gmsh_api.gmsh as gmsh

gmsh.initialize()

gmsh.option.setNumber("General.Terminal", 1)
gmsh.option.setNumber("Mesh.Algorithm", 5) # delquad
gmsh.option.setNumber("Mesh.RecombineAll", 1)

gmsh.model.add("square")
gmsh.model.geo.addPoint(0, 0, 0, 0.6, 1)
gmsh.model.geo.addPoint(1, 0, 0, 0.6, 2)
gmsh.model.geo.addPoint(1, 1, 0, 0.5, 3)
gmsh.model.geo.addPoint(0, 1, 0, 0.4, 4)
gmsh.model.geo.addLine(1, 2, 1)
gmsh.model.geo.addLine(2, 3, 2)
gmsh.model.geo.addLine(3, 4, 3)

# try automatic assignement of tag
line4 = gmsh.model.geo.addLine(4, 1)
gmsh.model.geo.addCurveLoop([1, 2, 3, line4], 1)
gmsh.model.geo.addPlaneSurface([1], 6)
gmsh.model.geo.synchronize()
gmsh.model.mesh.generate(2)
#gmsh.write("square.unv")

mesh = gmsh_api.Mesh.from_gmsh(gmsh)
print(mesh.nodes)
print(mesh.elements)

      nid         x         y    z
 1      1  0         0           0
 2      2  1         0           0
 3      3  1         1           0
 4      4  0         1           0
 5      5  0.5       0           0
 6      6  1         0.522774    0
 7      7  0.728708  1           0
 8      8  0.472136  1           0
 9      9  0.229485  1           0
10     10  0         0.786636    0
11     11  0         0.55051     0
12     12  0         0.289194    0
13     13  0.267268  0.304987    0
14     14  0.703727  0.740444    0
15     15  0.387068  0.62141     0
16     16  0.637319  0.370788    0
17     17  0.189356  0.818467    0

      pid    elid  type      n_nodes  nodes                 nidxs
 0      1      17  shell4          4  [9L, 17L, 15L, 8L]    [9L, 17L, 15L, 8L]
 1      1      18  shell4          4  [15L, 17L, 10L, 11L]  [15L, 17L, 10L, 11L]
 2      1      19  shell4          4  [10L, 17L, 9L, 4L]    [10L, 17L, 9L, 4L]
 3      1      20  shell4          4  [5L, 16L, 15L, 13L]   [5L, 16L, 15L, 13L]
 4      1      21  shell4          4  [6L, 14L, 15L, 16L]   [6L, 14L, 15L, 16L]
 5      1      22  shell4          4  [6L, 16L, 5L, 2L]     [6L, 16L, 5L, 2L]
 6      1      23  shell4          4  [15L, 14L, 7L, 8L]    [15L, 14L, 7L, 8L]
 7      1      24  shell4          4  [15L, 11L, 12L, 13L]  [15L, 11L, 12L, 13L]
 8      1      25  shell4          4  [5L, 13L, 12L, 1L]    [5L, 13L, 12L, 1L]
 9      1      26  shell4          4  [6L, 3L, 7L, 14L]     [6L, 3L, 7L, 14L]