input: Write a function to remove spaces from a given string.
  assert remove_spaces("Hello World") == "HelloWorld"
  assert remove_spaces("Python Programming Language") == "PythonProgrammingLanguage"
  assert remove_spaces("  Leading and trailing spaces  ") == "Leadingandtrailingspaces"
output: def remove_spaces(s: str) -> str:
      return s.replace(" ", "")