class_docstr: Fix a deprecated min_magnitude=None argument for complex numbers::
  
      st.complex_numbers(min_magnitude=None) -> st.complex_numbers(min_magnitude=0)
  
  Note that this should be run *after* ``HypothesisFixPositionalKeywonlyArgs``,
  in order to handle ``st.complex_numbers(None)``.
code: def leave_Arg(self, original_node, updated_node):
      if m.matches(
          updated_node,
          m.Arg(keyword=m.Name("min_magnitude"), value=m.Name("None")),
      ):
          return updated_node.with_changes(value=cst.Integer("0"))
      return updated_node
  
imports: import functools
  import importlib
  from inspect import Parameter, signature
  from typing import ClassVar, List
  import libcst
  import libcst.matchers
  from libcst.codemod import VisitorBasedCodemodCommand
label_desc: Use image node_id 1 for calling the HypothesisFixComplexMinMagnitude obj's underlying member method code with example usage: obj.leave_Arg(original_node, updated_node) and returns: updated_node, updated_node